Intravascular Injection of Contrast During Lumbar Discography: A Previously Unreported Complication

Objective.  Report a case of intravascular contrast injection during lumbar discography. Setting.  An academic University spine center. Patient.  Forty-year-old woman with L5-S1 degenerative disk disease and persistent low back pain. Intervention.  The patient failed to respond to multiple conservative treatments. In consideration of surgical treatment, discography was requested. Results.  A 22G needle was inserted to the central nucleus by a left posterolateral approach. Discography was performed at L4-5 and L5-S1. Testing was performed with pressure manometry, beginning with the L4-5 disk. The pressure increased with contrast injection in the manner of a normal disk. At 45 psi there was a sudden drop to 20 psi. Lateral views obtained during contrast injection demonstrated flow from a central nucleogram cephalad into the anterior epidural space. Images obtained with live fluoroscopy demonstrated a vascular flow pattern, confirmed with lateral and anterior-posterior views. The needle tip was repositioned anterior and superior. Repeat injection resulted in an identical vascular pattern. From the time the pressure dropped, contrast flowed in the vascular pattern without propagation of the nucleogram or increase in intradiscal pressure. The patient was asymptomatic throughout the injection at L4-5. Injection at L5-S1 demonstrated a severely degenerative nucleogram and reproduced the patient's usual low back pain. Conclusions.  Vascular uptake of contrast can occur during lumbar discography, even when the needle tip is ideally located.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73849/1/j.1526-4637.2008.00532.x.pd

The Regulatory Network of Natural Competence and Transformation of Vibrio cholerae

The human pathogen Vibrio cholerae is an aquatic bacterium frequently encountered in rivers, lakes, estuaries, and coastal regions. Within these environmental reservoirs, the bacterium is often found associated with zooplankton and more specifically with their chitinous exoskeleton. Upon growth on such chitinous surfaces, V. cholerae initiates a developmental program termed “natural competence for genetic transformation.” Natural competence for transformation is a mode of horizontal gene transfer in bacteria and contributes to the maintenance and evolution of bacterial genomes. In this study, we investigated competence gene expression within this organism at the single cell level. We provide evidence that under homogeneous inducing conditions the majority of the cells express competence genes. A more heterogeneous expression pattern was observable on chitin surfaces. We hypothesize that this was the case due to the heterogeneity around the chitin surface, which might vary extensively with respect to chitin degradation products and autoinducers; these molecules contribute to competence induction based on carbon catabolite repression and quorum-sensing pathways, respectively. Therefore, we investigated the contribution of these two signaling pathways to natural competence in detail using natural transformation assays, transcriptional reporter fusions, quantitative RT–PCR, and immunological detection of protein levels using Western blot analysis. The results illustrate that all tested competence genes are dependent on the transformation regulator TfoX. Furthermore, intracellular cAMP levels play a major role in natural transformation. Finally, we demonstrate that only a minority of genes involved in natural transformation are regulated in a quorum-sensing-dependent manner and that these genes determine the fate of the surrounding DNA. We conclude with a model of the regulatory circuit of chitin-induced natural competence in V. cholerae

A communal catalogue reveals Earth’s multiscale microbial diversity

Our growing awareness of the microbial world’s importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete characterization of Earth’s microbial diversity

A communal catalogue reveals Earth's multiscale microbial diversity

Our growing awareness of the microbial world's importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete characterization of Earth's microbial diversity.Peer reviewe

Experimental challenge studies in Vietnamese catfish, Pangasianodon hypophthalmus (Sauvage), exposed to Edwardsiella ictaluri and Aeromonas hydrophila

The two main diseases in the pangasius catfish industry are bacillary necrosis of Pangasianodon (BNP) and motile aeromonas septicaemia (MAS), where the aetiological agents have been identified as Edwardsiella ictaluri and Aeromonas hydrophila, respectively. In this study, apparently healthy Pangasianodon hypophthalmus were exposed to E. ictaluri, A. hydrophila or both bacterial species by intraperitoneal injection or immersion. There were 20 fish per treatment group, and the bacterial isolates used for the study were recovered from natural infections of BNP or MAS in farmed Vietnamese P. hypophthalmus. The results of the experimental infections mimicked the natural disease outbreaks reported from these pathogens in P. hypophthalmus. Furthermore, it was clearly demonstrated that E. ictaluri was only recovered from the fish exposed to the bacterium and not recovered from the animals receiving A. hydrophila