Training in vascular trauma surgery for non-vascular surgeons: Vascular trauma surgery skills course

Background

The experience of general and trauma surgeons in vascular trauma management has decreased with sub-specialization of surgery and working hours restrictions. We introduce a vascular trauma surgery skills course established to train German military surgeons prior to their deployment to conflict areas.

Methods

The intention and implementation of the vascular trauma course for non-vascular surgeons is described in detail.

Results

In hands-on courses, participants learn and train basic vascular surgical techniques on more realistic extremity, neck, and abdominal models with pulsatile vessels. A fundamental and an advanced course each provide military as well as civilian surgeons from different non-vascular specialties with a surgical skill set including direct vessel sutures, patch angioplasty, anastomosis, thrombectomy, and resuscitative endovascular balloon occlusion of the aorta (REBOA) in order to render them capable of managing major vascular injuries.

Conclusion

The experiences of this vascular trauma surgical skills course, initially established for military surgeons, can also be of use to all civilian general, visceral, and trauma surgeons occasionally facing traumatic or iatrogenic vascular injuries. Thus, the introduced vascular trauma course is valuable for all surgeons working in trauma centers.

The hrp gene locus of Pseudomonas solanacearum, which controls the production of a type III secretion system, encodes eight proteins related to components of the bacterial flagellar biogenesis complex

Five transcription units of the Pseudomonas solanacearum hrp gene cluster are required for the secretion of the HR-inducing PopA1 protein. The nucleotide sequences of two of these, units 1 and 3, have been reported. Here, we present the nucleotide sequence of the three other transcription units, units 2, 4 and 7, which are together predicted to code for 15 hrp genes. This brings the total number of Hrp proteins encoded by these five transcription units to 20, including HrpB, the positive regulatory protein, and HpaP, which is apparently not required for plant interactions. Among the 18 other proteins, eight belong to protein families regrouping proteins involved in type III secretion pathways in animal and plant bacterial pathogens and in flagellum biogenesis, while two are related solely to proteins involved in secretion systems. For the various proteins found to be related to P. solanacearum Hrp proteins, those in plant-pathogenic bacteria include proteins encoded by hrp genes. For Hrp-related proteins of animal pathogens, those encoded by the spa and mxi genes of Shigella flexneri and of Salmonella typhimurium and by the ysc genes of Yersinia are involved in type III secretion pathways. Proteins involved in flagellum biogenesis, which are related to Hrp proteins of P. solancearum, include proteins encoded by fli and flh genes of S. typhimurium, Bacillus subtilis and Escherichia coli and by mop genes of Erwinia carotovora. P. solanacearum Hrp proteins were also found to be related to proteins of Rhizobium fredii involved in nodulation specificity.

Evidence that the hrpB gene encodes a positive regulator of pathogenicity genes from Pseudomonas solanacearum

The hrp gene cluster of Pseudomonas solanacearum GMI1000 strain encodes functions that are essential for pathogenicity on tomato and for the elicitation of the hypersensitive response on tobacco. In this study, we present the nucleotide sequence of one of the hrp genes (hrpB) located at the left-hand end of the cluster and we show that hrpB encodes a positive regulator controlling the expression of hrp genes. hrpB has a coding capacity for a 477-amino-acid polypeptide, which shows significant similarity to several prokaryotic transcriptional activators including the AraC protein of Escherichia coli, the XylS protein of Pseudomonas putida and the VirF protein of Yersinia enterocolitica. The predicted hrpB gene product belongs to a family of bacterial regulators different from the previously described HrpS protein of the hrp gene cluster of Pseudomonas syringae pv. phaseolicola. Genetic evidence demonstrates that the hrpB gene product acts as a positive regulator of the expression in minimal medium of all but one of the putative transcription units of the hrp gene cluster and also controls the expression of genes located outside this cluster. We also show in this paper that the transcription of hrpB is induced in minimal medium and is partly autoregulated.

Transcriptional organization and expression of the large hrp gene cluster of Pseudomonas solanacearum

Cloning and localized mutagenesis of the larger cluster of hrp genes of Pseudomonas solanacearum strain GMI1000 allowed the definition of the borders of this cluster, which now extends about 2 kb to the left of the insert of the previously described plasmid pVir2 (Boucher et al. 1987, J. Bacteriol. 169:5626-5632). The size of the cluster has also been expanded 3 kb to the right to include a region previously described as dsp; our present data demonstrate that insertions occurring in these 3 kb lead to leaky mutations affecting both pathogenicity on tomato and ability to induce the hypersensitive response (HR) on tobacco. Therefore, the size of the entire hrp gene cluster is estimated to be about 22 kb. The use of transposon Tn5-B20, which promotes transcriptional gene fusions, allowed us to demonstrate that the hrp gene cluster is organized in a minimum of six transcriptional units, which are transcribed when the culture is grown in minimal medium but are repressed during growth in rich medium or in the presence of peptone or Casamino Acids. The level of expression in minimal medium is modulated by the carbon source provided; pyruvate is the best inducer. Under these conditions the level of expression observed in vitro appears to be representative of the actual expression observed in planta.

Pseudomonas solanacearum genes controlling both pathogenicity on tomato and hypersensitivity on tobacco are clustered

A pLAFR3 cosmid clone designated pVir2 containing a 25-kilobase (kb) DNA insert was isolated from a wild-type Pseudomonas solanacearum GMI1000 genomic library. This cosmid was shown to complement all but one of the nine Tn5-induced mutants which have been isolated after random mutagenesis and which have lost both pathogenicity toward tomato and ability to induce hypersensitive reaction (HR) on tobacco (hrp mutants). The insert is colinear with the genome and provides restoration of the HR-inducing ability when transferred into several Tn5-induced hrp mutants, but failed to complement deletion mutants extending on both sides of the pVir2 region. Localized mutagenesis demonstrated that the hrp genes are clustered within a 17.5-kb region of pVir2 and that this cluster probably extends on the genomic region adjacent to the pVir2 insert. A 3-kb region adjacent to the hrp cluster modulates aggressiveness toward tomato but does not control HR-inducing ability. Sequences within the hrp cluster of pVir2 have homology with the genomic DNA of Xanthomonas campestris strains representing eight different pathovars, suggesting that a set of common pathogenicity functions could be shared by P. solanacearum and X. campestris.