Interdisciplinary expert consensus document on management of type B aortic dissection

An expert multidisciplinary panel in the treatment of type B aortic dissection reviewed available literature to develop treatment algorithms using a consensus method. Data from 63 studies published from 2006 to 2012 were retrieved for a total of 1,548 patients treated medically, 1,706 patients who underwent open surgery, and 3,457 patients who underwent thoracic endovascular repair (TEVAR). For acute (first 2 weeks) type B aortic dissection, the pooled early mortality rate was 6.4% with medical treatment and increased to 10.2% with TEVAR and 17.5% with open surgery, mostly for complicated cases. Limited data for treatment of subacute (2 to 6 weeks after onset) type B aortic dissection showed an early mortality rate of 2.8% with TEVAR. In chronic (after 6 weeks) type B aortic dissection, 5-year survival of 60% to 80% was expected with medical therapy because complications were likely. If interventional treatment was applied, the pooled early mortality rate was 6.6% with TEVAR and 8.0% with open surgery. Medical treatment of uncomplicated acute, subacute, and chronic type B aortic dissection is managed with close image monitoring. Hemodynamic instability, organ malperfusion, increasing periaortic hematoma, and hemorrhagic pleural effusion on imaging identify patients with complicated acute type B aortic dissection requiring urgent aortic repair. Recurrence of symptoms, aortic aneurysmal dilation (>55 mm), or a yearly increase of >4 mm after the acute phase are predictors of adverse outcome and need for delayed aortic repair ("complicated chronic aortic dissections"). The expert panel is aware that this consensus document provides proposal for strategies based on nonrobust evidence for management of type B aortic dissection, and that literature results were largely heterogeneous and should be interpreted cautiously.

Interferon-inducible expression of APOBEC3 editing enzymes in human hepatocytes and inhibition of hepatitis B virus replication

Hypermutations in hepatitis B virus (HBV) DNA by APOBEC3 cytidine deaminases have been detected in vitro and in vivo, and APOBEC3G (A3G) and APOBEC3F (A3F) have been shown to inhibit the replication of HBV in vitro, but the presumably low or even absent hepatic expression of these enzymes has raised the question as to their physiological impact on HBV replication. We show that normal human liver expresses the mRNAs of APOBEC3B (A3B), APOBEC3C (A3C), A3F, and A3G. In primary human hepatocytes, interferon alpha (IFN-alpha) stimulated the expression of these cytidine deaminases up to 14-fold, and the mRNAs of A3G, A3F, and A3B reached expression levels of 10%, 3%, and 3%, respectively, relative to GAPDH mRNA abundance. On transfection, the full-length protein A3B(L) inhibited HBV replication in vitro as efficiently as A3G or A3F, whereas the truncated splice variant A3B(S) and A3C had no effect. A3B(L) and A3B(S) were detected predominantly in the nucleus of uninfected cells; however, in HBV-expressing cells both proteins were found also in the cytoplasm and were associated with HBV viral particles, similarly to A3G and A3F. Moreover, A3G, A3F, and A3B(L), but not A3B(S), induced extensive G-to-A hypermutations in a fraction of the replicated HBV genomes. In conclusion, the editing enzymes A3B(L), A3F, and most markedly A3G, which are expressed in liver and up-regulated by IFN-alpha in hepatocytes, are candidates to contribute to the noncytolytic clearance of HBV.

Selective immunisation strategy to protect newborns at risk for transmission of hepatitis B: retrospective audit of vaccine uptake

BACKGROUND: 90% of newborns infected perinatally will develop chronic hepatitis B infection with the risk of liver cirrhosis or hepatocellular carcinoma. In Switzerland, screening of all pregnant women for hepatitis B virus (HBV) has been recommended since 1983. Neonates at risk for perinatally acquired HBV are passively and actively immunised immediately after birth as well as at 1 and 6 months of age. The objective of this study was to evaluate the proportion of newborns immunised in accordance with the proposed vaccination schedule. METHODS: Patient records of 3997 mothers who gave birth to a liveborn infant during a two-year period at Zürich University Hospital were screened by computer. 128 women were identified as HBsAg positive or anti-HBc alone positive. Of 133 infants born to these mothers, complete data were available for 94 (71%). RESULTS: Immunisation was started in 88 infants (94%), but only in 78 (83%) within the first 24 hours of life. 85 (90%) received the 2nd immunisation but only 72 (77%) within the given time limit. 80 (85%) of the infants received the 3rd immunisation but only 69 (73%) within the correct time limit. In summary, only 51 (54%) of the infants at risk for HBV infection were immunised correctly (immunoglobulin within 24 hours and active prophylaxis at 0, 1 and 6 months). CONCLUSIONS: The success of the immunisation strategy following maternal screening and selective immunisation of newborns at risk for HBV infection is limited for various reasons (lack of screening results at birth, problems with correct documentation and communication). To overcome these drawbacks, selective vaccination strategy should be improved and general vaccination strategy, including infants, should be reconsidered.

Effects of point mutations in the cytidine deaminase domains of APOBEC3B on replication and hypermutation of hepatitis B virus in vitro

APOBEC3 cytidine deaminases hypermutate hepatitis B virus (HBV) and inhibit its replication in vitro. Whether this inhibition is due to the generation of hypermutations or to an alternative mechanism is controversial. A series of APOBEC3B (A3B) point mutants was analysed in vitro for hypermutational activity on HBV DNA and for inhibitory effects on HBV replication. Point mutations inactivating the carboxy-terminal deaminase domain abolished the hypermutational activity and reduced the inhibitory activity on HBV replication to approximately 40 %. In contrast, the point mutation H66R, inactivating the amino-terminal deaminase domain, did not affect hypermutations, but reduced the inhibition activity to 63 %, whilst the mutant C97S had no effect in either assay. Thus, only the carboxy-terminal deaminase domain of A3B catalyses cytidine deaminations leading to HBV hypermutations, but induction of hypermutations is not sufficient for full inhibition of HBV replication, for which both domains of A3B must be intact.

Technique to measure heats of reaction of Ti-B, Al-Ti-B, and Al-Ti-B4C powder blends

In this research, a modification to initiation aid ignition in bomb calorimetry that involves systemically blending levels of boron and potassium nitrate initiation aids with a bulk structural energetic elemental power blend is developed. A regression is used to estimate the nominal heat of reaction for the primary reaction. The technique is first applied to the synthesis of TiB2 as a validation study to see if close proximity to literature values can be achieved. The technique is then applied to two systems of interest, Al-Ti-B, and Al-Ti-B4C. In all three investigations, x-ray diffraction is used to characterize the product phases of the reactions to determine the extent and identity of the product phases and any by-products that may have formed as a result of adding the initiation aid. The experimental data indicates the technique approximates the heat of reaction value for the synthesis of TiB2 from Ti-B powder blends and the formation of TiB2 is supported by volume fraction analysis by x-ray diffraction. Application to the Al-Ti-B and Al-Ti-B4C blends show some correlation with variation of the initiation aid, with x-ray diffraction showing the formation of equilibrium products. However, these blends require further investigation to resolve more complex interactions and rule out extraneous variables.

Adenosine Kinase of T. b. Rhodesiense identified as the putative target of 4-[5-(4-phenoxyphenyl)-2H-pyrazol-3-yl]morpholine using chemical proteomics

BACKGROUND: Human African trypanosomiasis (HAT), a major parasitic disease spread in Africa, urgently needs novel targets and new efficacious chemotherapeutic agents. Recently, we discovered that 4-[5-(4-phenoxyphenyl)-2H-pyrazol-3-yl]morpholine (compound 1) exhibits specific antitrypanosomal activity with an IC(50) of 1.0 microM on Trypanosoma brucei rhodesiense (T. b. rhodesiense), the causative agent of the acute form of HAT. METHODOLOGY/PRINCIPAL FINDINGS: In this work we show adenosine kinase of T. b. rhodesiense (TbrAK), a key enzyme of the parasite purine salvage pathway which is vital for parasite survival, to be the putative intracellular target of compound 1 using a chemical proteomics approach. This finding was confirmed by RNA interference experiments showing that down-regulation of adenosine kinase counteracts compound 1 activity. Further chemical validation demonstrated that compound 1 interacts specifically and tightly with TbrAK with nanomolar affinity, and in vitro activity measurements showed that compound 1 is an enhancer of TbrAK activity. The subsequent kinetic analysis provided strong evidence that the observed hyperactivation of TbrAK is due to the abolishment of the intrinsic substrate-inhibition. CONCLUSIONS/SIGNIFICANCE: The results suggest that TbrAK is the putative target of this compound, and that hyperactivation of TbrAK may represent a novel therapeutic strategy for the development of trypanocides.

Serotype distribution and antimicrobial susceptibility of group B streptococci in pregnant women: results from a Swiss tertiary centre.

OBJECTIVE To evaluate the rates of penicillin, clindamycin and erythromycin resistance and the serotype distribution among isolates of group B streptococcus (GBS) obtained from pregnant women at the University Hospital of Bern in Switzerland. METHODS We prospectively collected screening samples for GBS colonisation at the University Women's Hospital Bern, Switzerland, between March 2009 and August 2010. We included 364 GBS isolates collected from vaginal, cervical or vaginal-perianal swabs at any gestation time. The minimal inhibitory concentrations for penicillin, clindamycin and erythromycin were established using Etest with 24 hours of incubation, and inducible clindamycin resistance was tested with double disk diffusion tests. Serotyping was done with a rapid latex agglutination test or, if not conclusive, with polymerase chain-reaction (PCR) testing. We looked for significant associations between resistance patterns, age groups, serotype and ethnicity. RESULTS All isolates were susceptible to penicillin. Resistance rates were 14.5% for erythromycin and 8.2% for clindamycin. Of 364 isolates, 5.8% were susceptible to clindamycin but not to erythromycin, although demonstrating inducible clindamycin resistance. Hence, the final reported clindamycin resistance rate was 14%. Serotype III was the most frequent serotype (29%), followed by V (25%) and Ia (19%). Serotype V was associated with erythromycin resistance (p = 0.0007). In comparison with all other ethnicities, patients from Asia showed a higher proportion of erythromycin and clindamycin resistance (p = 0.018). No significant association between resistance patterns and age groups was found. CONCLUSION In pregnant women with GBS colonisation, penicillin is the antibiotic of choice for intrapartum prophylaxis to prevent neonatal early-onset GBS sepsis. In women with penicillin allergy and at high risk for anaphylactic reaction, clindamycin may be an alternative. The resistance rate for clindamycin at our institution was 14%; therefore, susceptibility must be tested before administration.

The inhibition of lipid transfer protein by negatively charged liposomes modifies the therapeutic index of amphotericin B

We have shown that liposomal amphotericin B (L-AmpB) decreased renal toxicity and maintains the antifungal activity of amphotericin B (AmpB). We have also observed that L-AmpB is predominantly associated with high density lipoproteins (HDL) as compared to Fungizone (AmpB + deoxycholate). The present experiments were designed to assess the biological relevance of transferring AmpB to HDL. We observed that AmpB was less toxic to kidney cells when associated with HDL, however AmpB toxicity was maintained when associated with LDL. To further understand how HDL-associated AmpB reduces renal cell toxicity the presence of HDL and LDL receptors in this cell line was determined. We observed that these cells expressed high and low affinity LDL receptors, but only low affinity HDL receptors. The reduced renal cell toxicity of HDL-associated AmpB may be due to its lack of interaction with renal cells because of the absence of HDL receptors. Since AmpB interacts with cholesteryl esters whose transfer among lipoproteins is regulated by Lipid transfer Protein (LTP), the role of LTP on the distribution of AmpB to HDL and LDL was next examined. We found that negatively charged liposomes significantly reduced LTP-mediated transfer of CE between HDL and LDL, independent of the presence of AmpB, while Fungizone only significantly inhibited CE transfer at one concentration tested (20$\mu$g/ml). Therefore, we believe that the decreased renal toxicity of L-AmpB is related to its predominant distribution to HDL which is regulated by the inhibition of LTP activity. ^

A cladistic analysis of apolipoprotein B gene variation and plasma lipid and apolipoprotein B levels, using familial data

Any functionally important mutation is embedded in an evolutionary matrix of other mutations. Cladistic analysis, based on this, is a method of investigating gene effects using a haplotype phylogeny to define a set of tests which localize causal mutations to branches of the phylogeny. Previous implementations of cladistic analysis have not addressed the issue of analyzing data from related individuals, though in human studies, family data are usually needed to obtain unambiguous haplotypes. In this study, a method of cladistic analysis is described in which haplotype effects are parameterized in a linear model which accounts for familial correlations. The method was used to study the effect of apolipoprotein (Apo) B gene variation on total-, LDL-, and HDL-cholesterol, triglyceride, and Apo B levels in 121 French families. Five polymorphisms defined Apo B haplotypes: the signal peptide Insertion/deletion, Bsp 1286I, XbaI, MspI, and EcoRI. Eleven haplotypes were found, and a haplotype phylogeny was constructed and used to define a set of tests of haplotype effects on lipid and apo B levels.^ This new method of cladistic analysis, the parametric method, found significant effects for single haplotypes for all variables. For HDL-cholesterol, 3 clusters of evolutionarily-related haplotypes affecting levels were found. Haplotype effects accounted for about 10% of the genetic variance of triglyceride and HDL-cholesterol levels. The results of the parametric method were compared to those of a method of cladistic analysis based on permutational testing. The permutational method detected fewer haplotype effects, even when modified to account for correlations within families. Simulation studies exploring these differences found evidence of systematic errors in the permutational method due to the process by which haplotype groups were selected for testing.^ The applicability of cladistic analysis to human data was shown. The parametric method is suggested as an improvement over the permutational method. This study has identified candidate haplotypes for sequence comparisons in order to locate the functional mutations in the Apo B gene which may influence plasma lipid levels. ^

The effects of ultraviolet B radiation on immune responses to {\it Borrelia burgdorferi}, the causative agent of Lyme disease

Ultraviolet B (UVB) radiation, in addition to being carcinogenic, is also immunosuppressive. Immunologically, UVB induces suppression locally, at the site of irradiation, or systemically, by inducing the production of a variety of immunosuppressive cytokines. Systemic effects include suppression of delayed-type hypersensitivity (DTH) responses to a variety of antigens (e.g. haptens, proteins, bacterial antigens, or alloantigens). One of the principal mediators of UV-induced immune suppression is the T helper-2 (Th2) cytokine interleukin-10 (IL-10); this suggests that UV irradiation induces suppression by shifting the immune response from a Th1 (cellular) to a Th2 (humoral) response. These "opposing" T helper responses are usually mutually exclusive, and polarized Th1 or Th2 responses may lead to either protection from infection or increased susceptibility to disease, depending on the infectious agent and the route of infection.^ This study examines the effects of UVB irradiation on cellular and humoral responses to Borrelia burgdorferi (Bb), the causative agent of Lyme disease (LD) in both immunization and infectious disease models; in addition, it examines the role of T cells in protection from and pathology of Bb infection. Particular emphasis is placed on the Bb-specific antibody responses following irradiation since UVB effects on humoral immunity are not fully understood. Mice were irradiated with a single dose of UV and then immunized (in complete Freund's adjuvant) or infected with Bb (intradermally at the base of the tail) in order to examine both DTH and antibody responses in both systems. UVB suppressed the Th1-associated antibodies IgG2a and IgG2b in both systems, as well as the DTH response to Bb in a dose dependent manner. Injection of anti-IL-10 antibody into UV-irradiated mice within 24 h after UV exposure restored the DTH response, as well as the Th1 antibody (IgG2a and IgG2b) response. In addition, injecting recombinant IL-10 mimicked some of the effects of UV radiation.^ Bb-specific Th1 T cell lines (BAT2.1-2.3) were generated to examine the role of T cells in Lyme borreliosis. All lines were CD4$\sp+,$ $\alpha\beta\sp+$ and proliferated specifically in response to Bb. The BAT2 cell lines not only conferred a DTH response to naive C3H recipients, but reduced the number of organisms recovered from the blood and tissues of mice infected with Bb. Furthermore, BAT2 cell lines protected mice from Bb-induced periarthritis. ^