Alveococcosis of the liver - strategy of surgical treatment with special focus on liver transplantation.

BACKGROUND: Echinococcosis is a zoonosis caused by infestation with any of 4 (of the 16) members of the Echinococcus genus, namely Echinococcus granulosus, Echinococcus multilocularis, Echinococcus oligarthus, and Echinococcus vogelii. The aim of this retrospective analysis was to present the outcomes of patients undergoing liver resection and liver transplantation (LT) for E. multilocularis infection. METHODS: A total of 44 patients who underwent surgical treatment of E. multilocularis infection in the period between 1989 and 2014 were included in the study cohort and retrospectively analyzed. RESULTS: LT was performed in 22 patients (50.0%), including 4 of 26 patients undergoing initial non-transplant management. Non-transplant procedures comprised liver resection in 23 patients (88.5%), diagnostic laparoscopy in 2 (7.7%), and left adrenalectomy in 1 patient (3.8%). Post-transplantation survival rates were 90%, 85%, and 75% at 1, 5, and 10 years, respectively. CONCLUSION: In conclusion, LT for E. multilocularis infection is a safe and effective treatment method.

The circle is broken: telomere resolution in linear replicons.

Linear DNA molecules with covalently closed hairpin ends (telomeres) exist in a wide variety of organisms. Telomere resolution, a DNA breakage and reunion reaction in which replicated telomeres are processed into hairpin ends, is now known to be a common theme in poxviruses, Borrelia burgdorferi and Escherichia coli phage N15. Candidate proteins that may perform this reaction have recently been identified in poxviruses. Moreover, the first purification and definitive identification of a telomere resolvase has been reported for phage N15. This protein is the prototype for a new class of DNA enzyme that performs a unique reaction. Advances in the study of telomere resolution in poxviruses, B. burgdorferi and E. coli phage N15 are discussed.

Supercoiling-dependent site-specific binding of HU to naked Mu DNA.

Using HU chemical nucleases to probe HU-DNA interactions, we report here for the first time site-specific binding of HU to naked DNA. An unique feature of this interaction is the absolute requirement for negative DNA supercoiling for detectable levels of site-specific DNA binding. The HU binding site is the Mu spacer between the L1 and L2 transposase binding sites. Our results suggest recognition of an altered DNA structure which is induced by DNA supercoiling. We propose that recruitment of HU to this naked DNA site induces the DNA bending required for productive synapsis and transpososome assembly. Implications of HU as a supercoiling sensor with a potential in vivo regulatory role are discussed. Finally, using HU nucleases we have also shown that non-specific DNA binding by HU is stimulated by increasing levels of supercoiling.

VSG gene control and infectivity strategy of metacyclic stage Trypanosoma brucei.

As the metacyclic trypanosome stage develops in the tsetse fly salivary glands, it initiates expression of variant surface glycoproteins (VSGs) and does so by each cell activating, at random, one from a small subset of metacyclic VSG (M-VSG) genes. Whereas differential activation of individual VSG genes in the bloodstream occurs as a function of time, to evade waves of antibody, it is believed that the aim in the metacyclic stage is simultaneously to generate population diversity. M-VSG genes are activated in their telomeric loci and belong to monocistronic transcription units, unlike all other known trypanosome protein-coding genes, which appear to be transcribed polycistronically. The promoters of these metacyclic expression sites (M-ESs) have the unique property, in this organism, of being switched on and off in a life-cycle stage specific pattern. We have found that the 1.22 M-ES promoter is regulated according to life cycle stage, differential control being exerted through different elements of the promoter and under the influence of its genomic locus. We have characterized in detail the telomeres containing the 1.22 and 1.61 M-ESs. Upstream of the M-ES is a possibly haploid, non-transcribed region with some degenerate sequences homologous with expression site associated genes (ESAGs) that occur in bloodstream VSG expression sites. Further upstream (respectively, 22 and 13 kb upstream of the 1.22 and 1.61 VSG genes) are alpha-amanitin sensitive transcription units that may be polycistrons and are transcribed in all examined life cycle stages. They contain a number of genes. The differences between metacyclic and bloodstream ESs may have important consequences for life cycle regulation, genetic stability, phenotype complexity and adaptability of the metacyclic stage as it infects different host species.

Impact of tumor characteristic on the outcome of liver transplantation in patients with hepatocellular carcinoma.

INTRODUCTION: Orthotopic liver transplantation (OLT) is a well-established treatment for cirrhotic patients with hepatocellular carcinoma (HCC) who meet the Milan criteria. The aim of this study was to identify predictors of survival among 65 patients with HCC in cirrhotic livers who underwent liver transplantation (OLT). METHODS: From January 2001 to December 2008, we performed 655 OLT in 615 patients. HCC was diagnosed in 58 patients before OLT and in 65 by histological examination of the explanted livers; 74% of the patients met Milan criteria by histological examination. RESULTS: The median follow-up was 27 months (range = 1-96). We analyzed patient age and gender, etiology of liver disease, Child score at transplantation, rejection episodes, tumor number/size, vascular invasion, and differentiation grade. There was no significant difference in survival among patients grouped according to the Model for End-stage Liver Disease staging system for HCC. The 5-year survival of patients with low differentiated (G3) HCC was significantly worse than that of those with moderately differentiated (G2) or well-differentiated (G1) HCC: 50%, 81%, and 86% respectively, (P < .01). Patients with microvascular invasion displayed a worse 5-year survival than those without vascular invasion (42% vs 80%; P < .01). CONCLUSIONS: The analysis indicated that the histological grade of the tumors and evidences of microscopic vascular invasion were the most useful predictive factors for overall survival among patients with cirrhosis after liver transplantation for HCC.

Site-specific DNA binding and bending by the Borrelia burgdorferi Hbb protein.

The Borrelia burgdorferi Hbb protein shows sequence similarity to members of the Escherichia coli HU/integration host factor (IHF) family of DNA accessory factors. We have overexpressed the hbb gene product in E. coli and purified the protein to near homogeneity. Biochemical analyses have revealed that Hbb has unique properties and is neither a strict HU nor IHF analogue. Hbb was found to bind specifically to a site in the putative origin of DNA replication between dnaA and dnaN. DNA footprinting studies have shown that this site is unrelated to the consensus sequence recognized by IHF proteins. Hbb induces a dramatic bend (> 126 degrees ) at this site and was also shown to restrain negative supercoils efficiently upon DNA binding. These features of the protein suggest that Hbb may act as a DNA accessory factor that facilitates the assembly of higher order protein-DNA complexes, such as those involved in DNA replication, transcription, recombination, packaging and perhaps other DNA metabolic processes unique to Borrelia.