Spezielle Therapiesituationen beim metastasierten kolorektalen Karzinom

Specific Treatment Situations in Metastatic Colorectal Cancer As far as the management of primary resectable liver metastases is concerned, three approaches are currently competing with each other: surgery alone, surgery with pre- and postoperative chemotherapy, and surgery with postoperative chemotherapy alone. The core of the argument for pre- and postoperative chemotherapy in these patients is the European Organisation for Research and Treatment of Cancer (EORTC) 40983 study, which concluded that, in comparison with surgery alone, perioperative chemotherapy improved the 3-year progression-free survival (PFS) by 7 months. In contrast to this, there are two smaller studies - at a somewhat lower strength of evidence - indicating that adjuvant chemotherapy extends PFS by 9.1 months compared with surgery alone. In Germany, the adjuvant approach continues to be favored in many places; this can also be seen in the formulation of the S3 guideline. In patients with unresectable liver metastases - with the associated difficulty of classification due to the lack of clear and definitive criteria preoperative systemic therapy to induce `conversion' is indicated, in order to allow secondary resection. In KRAS wild-type tumors, high response rates ( in terms of a reduction in size of the metastases, such as according to RECIST ( Response Evaluation Criteria in Solid Tumors)) and a high conversion rate are achieved using a cetuximab/chemotherapy combination. Triple chemotherapy combinations with 5-fluorouracil (5-FU), oxaliplatin and irinotecan also produce high response rates. Bevacizumab/chemotherapy combinations have led to a high number of complete and partial pathohistological remissions in phase II studies; these seem to correlate with long survival times. In the absence of long-term survival data, it therefore seems to remain unclear as to what is the best parameter to use in order to assess the success of preoperative treatment. Lung metastases, too, or local peritoneal carcinomatosis can nowadays be operated on in selected patients with a good prospect of long-term remission or even cure. The surgery should, however, generally only be carried out in experienced centers, especially in the case of peritoneal carcinomatosis. For synchronous metastasization, the appropriate management depends on the size and extent of liver metastases and of the primary tumor. Small, peripherally lying and safely resectable liver metastases can be removed before or at the same time as the primary tumor, especially if a hemicolectomy is being carried out. If the metastases are unresectable and there is no bleeding or stenosis, the primary tumor can also be left in situ and systemic chemotherapy can be carried out first. However, it should be borne in mind that, according to current data, palliative resection of the primary tumor combined with systemic therapy leads to longer overall survival than does chemotherapy alone. Whether resection or chemotherapy should be done first therefore depends on the patient's clinical situation

Bartonella Adhesin A Mediates a Proangiogenic Host Cell Response

Bartonella henselae causes vasculoproliferative disorders in humans. We identified a nonfimbrial adhesin of B. henselae designated as Bartonella adhesin A (BadA). BadA is a 340-kD outer membrane protein encoded by the 9.3-kb badA gene. It has a modular structure and contains domains homologous to the Yersinia enterocolitica nonfimbrial adhesin (Yersinia adhesin A). Expression of BadA was restored in a BadA-deficient transposon mutant by complementation in trans. BadA mediates the binding of B. henselae to extracellular matrix proteins and to endothelial cells, possibly via β1 integrins, but prevents phagocytosis. Expression of BadA is crucial for activation of hypoxia-inducible factor 1 in host cells by B. henselae and secretion of proangiogenic cytokines (e.g., vascular endothelial growth factor). BadA is immunodominant in B. henselae–infected patients and rodents, indicating that it is expressed during Bartonella infections. Our results suggest that BadA, the largest characterized bacterial protein thus far, is a major pathogenicity factor of B. henselae with a potential role in the induction of vasculoproliferative disorders

Structure of the Head of the Bartonella Adhesin BadA

Trimeric autotransporter adhesins (TAAs) are a major class of proteins by which pathogenic proteobacteria adhere to their hosts. Prominent examples include Yersinia YadA, Haemophilus Hia and Hsf, Moraxella UspA1 and A2, and Neisseria NadA. TAAs also occur in symbiotic and environmental species and presumably represent a general solution to the problem of adhesion in proteobacteria. The general structure of TAAs follows a head-stalk-anchor architecture, where the heads are the primary mediators of attachment and autoagglutination. In the major adhesin of Bartonella henselae, BadA, the head consists of three domains, the N-terminal of which shows strong sequence similarity to the head of Yersinia YadA. The two other domains were not recognizably similar to any protein of known structure. We therefore determined their crystal structure to a resolution of 1.1 Å. Both domains are β-prisms, the N-terminal one formed by interleaved, five-stranded β-meanders parallel to the trimer axis and the C-terminal one by five-stranded β-meanders orthogonal to the axis. Despite the absence of statistically significant sequence similarity, the two domains are structurally similar to domains from Haemophilus Hia, albeit in permuted order. Thus, the BadA head appears to be a chimera of domains seen in two other TAAs, YadA and Hia, highlighting the combinatorial evolutionary strategy taken by pathogens

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Analysis of Bartonella Adhesin A Expression Reveals Differences between Various B. henselae Strains

Bartonella henselae causes cat scratch disease and the vasculoproliferative disorders bacillary angiomatosis and peliosis hepatis in humans. One of the best known pathogenicity factors of B. henselae is Bartonella adhesin A (BadA), which is modularly constructed, consisting of head, neck/stalk, and membrane anchor domains. BadA is important for the adhesion of B. henselae to extracellular-matrix proteins and endothelial cells (ECs). In this study, we analyzed different B. henselae strains for BadA expression, autoagglutination, fibronectin (Fn) binding, and adhesion to ECs. We found that the B. henselae strains Marseille, ATCC 49882, Freiburg 96BK3 (FR96BK3), FR96BK38, and G-5436 express BadA. Remarkably, BadA expression was lacking in a B. henselae ATCC 49882 variant, in strains ATCC 49793 and Berlin-1, and in the majority of bacteria of strain Berlin-2. Adherence of B. henselae to ECs and Fn reliably correlated with BadA expression. badA was present in all tested strains, although the length of the gene varied significantly due to length variations of the stalk region. Sequencing of the promoter, head, and membrane anchor regions revealed only minor differences that did not correlate with BadA expression, apart from strain Berlin-1, in which a 1-bp deletion led to a frameshift in the head region of BadA. Our data suggest that, apart from the identified genetic modifications (frameshift deletion and recombination), other so-far-unknown regulatory mechanisms influence BadA expression. Because of variations between and within different B. henselae isolates, BadA expression should be analyzed before performing infection experiments with B. henselae

Characterization of the Vibrio cholerae E1 Tor lipase operon lipAb and a protease gene downstream of the hly region

We have cloned and sequenced a region encoding a lipase operon and a putative, previously uncharacterized metalloprotease of Vibrio cholerae O1. These lie downstream of hlyA and hlyB, which encode the El Tor hemolysin and methyl-accepting chemotactic factor, respectively. Previous reports identified the hlyC gene downstream of hlyAB, encoding an 18.3-kDa protein. However, we now show that this open reading frame (ORF) encodes a 33-kDa protein, and since the amino acid sequence is highly homologous to the triacylglyceride- specific lipase of Pseudomonas spp., hlyC has been renamed lipA. LipA contains the highly conserved pentapeptide and catalytic triad amino acid regions of the catalytic sites of other lipases. The region downstream of lipA has been sequenced and has revealed ORFs lipB and prtV. The amino acid sequence of lipB is homologous to those of the accessory lipase proteins (lipase-specific foldase) required by Pseudomonas and various other bacterial species for the production of mature active lipase, and in agreement with this, we show that both lipA and lipB are required to restore a lipase-deficient lipA null mutant of V. cholerae. The intergenic stop codon for lipA overlaps the ribosome-binding site for lipB, and a stem-loop resembling a rho-independent terminator is present immediately downstream from lipB, suggesting that lipA and lipB form a lipase operon in V. cholerae. prtV lies downstream of lipAB but is transcribed in the opposite direction and is predicted to share the same putative transcriptional terminator with lipAB. The zinc-binding and catalytic domains conserved among many metalloproteases are present in PrtV, which is highly homologous to the immune inhibitor A (InA) metalloprotease of Bacillus thuringiensis. PrtV was visualized as approximately 102 kDa, which is consistent with the coding capacity of the gene. The genetic organization of this region suggests that it is possibly part of a pathogenicity island, encoding products capable of damaging host cells and/or involved in nutrient acquisition by V. cholerae. However, neither lipA nor prtV null mutants were attenuated in the infant mouse model, nor did they exhibit reduced colonization potential compared with wild type in competition experiments.Monica A. Ogierman, Angelo Fallarino, Tanja Riess, Susan G. Williams, Stephen R. Attridge, and Paul A. Mannin

Bartonella quintana Variably Expressed Outer Membrane Proteins Mediate Vascular Endothelial Growth Factor Secretion but Not Host Cell Adherence

Bartonella quintana causes trench fever, endocarditis, and the vasculoproliferative disorders bacillary angiomatosis and peliosis hepatis in humans. Little is known about the interaction of this pathogen with host cells. We attempted to elucidate the interaction of B. quintana with human macrophages (THP-1) and epithelial cells (HeLa 229). Remarkably, only B. quintana strain JK-31 induced secretion of vascular endothelial growth factor (VEGF) from THP-1 and HeLa 229 cells upon infection similar to the secretion induced by B. henselae Marseille, whereas other strains (B. quintana 2-D70, B. quintana Toulouse, and B. quintana Munich) did not induce such secretion. Immunofluorescence testing and electron microscopy revealed that the B. quintana strains unable to induce VEGF secretion did not express the variable outer membrane proteins (Vomps) on their surfaces. Surprisingly, the increase in VEGF secretion mediated by B. quintana JK-31 was not paralleled by elevated host cell adherence rates compared with the rates for Vomp-negative B. quintana strains. Our results suggest that the Vomps play a leading role in the angiogenic reprogramming of host cells by B. quintana but not in the adherence to host cells

Analysis of a Novel Insect Cell Culture Medium-Based Growth Medium for Bartonella Species▿

Human- and animal-pathogenic Bartonella species are fastidious and slow-growing bacteria difficult to isolate and cultivate. We describe a novel, easy-to-prepare liquid medium for the fast and reliable growth of several Bartonella spp. that does not affect bacterial protein expression patterns or interactions with host cells

Spinocerebellar ataxia type 15: diagnostic assessment, frequency, and phenotypic features

International audienceBackground: To guide time- and cost-efficient analyses of the increasing number of autosomal-dominant spinocerebellar ataxia genes (SCAs), more information about frequency distributions, phenotypic characteristics and optimal diagnostic strategies is warranted. Objective: To assess the prevalence and phenotypic spectrum of SCA15 and to confirm multiplex ligation-dependent probe amplification (MLPA) as a robust and efficient strategy for routine molecular diagnosis. Methods: Fifty-six German SCA families negative for common repeat expansions were screened for ITPR1 deletions by MLPA. Samples with conspicuous MLPA data were additionally assessed by high-density SNP-array to confirm MLPA results and further determine the size of deletions. The phenotype of patients harbouring ITPR1 deletions was characterized by standardized clinical, electrophysiological and imaging assessment. Results: SCA15 accounted for 8.9% (5/56) of SCA families negative for common SCA repeat expansions. All deletions detected by MLPA were confirmed by SNP-array. One of the ITPR1 deletions preserved exons 1 and 2 in the 5' prime UTR of the ITPR1 gene. All SCA15 patients (n=10) presented with slowly progressive cerebellar ataxia and vermal cerebellar atrophy, while clinical and electrophysiological signs of extra-cerebellar affection were mild and more variable. Conclusions: SCA15 is the most common non-trinucleotide repeat SCA in Central Europe. Screening for ITPR1 deletions should be considered in patients with slowly progressive SCA, vermal cerebellar atrophy and prominent tremor after excluding common SCA repeat expansions. Promotor and exon 2 of ITPR1 may be preserved from the deletion in some cases of SCA15