Bariatric surgery: an overview.

The rise of obesity in the UK has led to greater numbers of patients requiring bariatric surgery. This article provides an overview of the two main types of surgery available: laparoscopic adjustable gastric band and Roux-en-Y gastric bypass surgery. The nurse's role in pre-operative assessment and post-operative care are discussed. Strategies to maintain weight loss are suggested to ensure optimum outcomes of surgery and to improve patients' quality of life.

Safety and Immunogenicity of a Novel Recombinant Simian Adenovirus ChAdOx2 as a Vectored Vaccine.

Adenovirus vectored vaccines are a highly effective strategy to induce cellular immune responses which are particularly effective against intracellular pathogens. Recombinant simian adenovirus vectors were developed to circumvent the limitations imposed by the use of human adenoviruses due to widespread seroprevalence of neutralising antibodies. We have constructed a replication deficient simian adenovirus-vectored vaccine (ChAdOx2) expressing 4 genes from the Mycobacterium avium subspecies paratuberculosis (AhpC, Gsd, p12 and mpa). Safety and T-cell immunogenicity results of the first clinical use of the ChAdOx2 vector are presented here. The trial was conducted using a 'three-plus-three' dose escalation study design. We demonstrate the vaccine is safe, well tolerated and immunogenic.

A simian-adenovirus-vectored rabies vaccine suitable for thermostabilisation and clinical development for low-cost single-dose pre-exposure prophylaxis.

BACKGROUND: Estimates of current global rabies mortality range from 26,000 to 59,000 deaths per annum. Although pre-exposure prophylaxis using inactivated rabies virus vaccines (IRVs) is effective, it requires two to three doses and is regarded as being too expensive and impractical for inclusion in routine childhood immunization programmes. METHODOLOGY/ PRINCIPAL FINDINGS: Here we report the development of a simian-adenovirus-vectored rabies vaccine intended to enable cost-effective population-wide pre-exposure prophylaxis against rabies. ChAdOx2 RabG uses the chimpanzee adenovirus serotype 68 (AdC68) backbone previously shown to achieve pre-exposure protection against rabies in non-human primates. ChAdOx2 differs from AdC68 in that it contains the human adenovirus serotype 5 (AdHu5) E4 orf6/7 region in place of the AdC68 equivalents, enhancing ease of manufacturing in cell lines which provide AdHu5 E1 proteins in trans. We show that immunogenicity of ChAdOx2 RabG in mice is comparable to that of AdC68 RabG and other adenovirus serotypes expressing rabies virus glycoprotein. High titers of rabies virus neutralizing antibody (VNA) are elicited after a single dose. The relationship between levels of VNA activity and rabies virus glycoprotein monomer-binding antibody differs after immunization with adenovirus-vectored vaccines and IRV vaccines, suggesting routes to further enhancement of the efficacy of the adenovirus-vectored candidates. We also demonstrate that ChAdOx2 RabG can be thermostabilised using a low-cost method suitable for clinical bio-manufacture and ambient-temperature distribution in tropical climates. Finally, we show that a dose-sparing effect can be achieved by formulating ChAdOx2 RabG with a simple chemical adjuvant. This approach could lower the cost of ChAdOx2 RabG and other adenovirus-vectored vaccines. CONCLUSIONS/ SIGNIFICANCE: ChAdOx2 RabG may prove to be a useful tool to reduce the human rabies death toll. We have secured funding for Good Manufacturing Practice- compliant bio-manufacture and Phase I clinical trial of this candidate.

Human vaccination against RH5 induces neutralizing antimalarial antibodies that inhibit RH5 invasion complex interactions.

The development of a highly effective vaccine remains a key strategic goal to aid the control and eventual eradication of Plasmodium falciparum malaria. In recent years, the reticulocyte-binding protein homolog 5 (RH5) has emerged as the most promising blood-stage P. falciparum candidate antigen to date, capable of conferring protection against stringent challenge in Aotus monkeys. We report on the first clinical trial to our knowledge to assess the RH5 antigen - a dose-escalation phase Ia study in 24 healthy, malaria-naive adult volunteers. We utilized established viral vectors, the replication-deficient chimpanzee adenovirus serotype 63 (ChAd63), and the attenuated orthopoxvirus modified vaccinia virus Ankara (MVA), encoding RH5 from the 3D7 clone of P. falciparum. Vaccines were administered i.m. in a heterologous prime-boost regimen using an 8-week interval and were well tolerated. Vaccine-induced anti-RH5 serum antibodies exhibited cross-strain functional growth inhibition activity (GIA) in vitro, targeted linear and conformational epitopes within RH5, and inhibited key interactions within the RH5 invasion complex. This is the first time to our knowledge that substantial RH5-specific responses have been induced by immunization in humans, with levels greatly exceeding the serum antibody responses observed in African adults following years of natural malaria exposure. These data support the progression of RH5-based vaccines to human efficacy testing.

Formulation of a microparticle carrier for oral polyplex-based DNA vaccines.

Oral induction of a disseminated mucosal immune response with polyplex-based DNA vaccines requires the delivery of intact polyplexes (polyelectrolyte complexes formed by self-assembly of plasmid DNA with a cationic polymer) to subepithelial lymphoid tissue (e.g. Peyer's patches) within the gastrointestinal tract. This work describes the formulation of a microparticle polyplex carrier allowing the potential of this approach to be realised. PEGylated PEI/DNA polyplexes (DNA concentration 20 microg/ml) formed at N/P 5:0 (defined as the ratio of polycation amino groups to DNA phosphates) were stable to salt-induced aggregation and could be concentrated to a final DNA concentration of 1 mg/ml without polyplex size increase. Polyplexes containing 1:1 polyethylene glycol (PEG)/polyethylenimine (PEI) ratio (mass/mass) gave similar levels of luciferase gene expression in B16F10 cells compared to non-PEG complexes. Poly-(D,L-lactide-co-glycolide) (PLGA) microparticles containing PEGylated polyplexes (approximately 17% DNA encapsulation efficiency) were formulated using a modified double emulsion solvent evaporation method. The microencapsulation and release of intact polyplexes from the microparticle carrier was demonstrated using polyanion (heparin sulfate and poly(aspartic acid) (PAA)) displacement techniques and electron microscopy. Microparticles containing PEGylated polyplexes (24 microg beta-galactosidase DNA) were given orally to Wistar rats. Significant transgene expression (compared to background) was found in peripheral tissue (spleen) 72 h after administration. This work demonstrates the potential application of microparticle carriers for mucosal polyplex-based vaccination.

Tumour necrosis factor-alpha increases extravasation of virus particles into tumour tissue by activating the Rho A/Rho kinase pathway.

Tumour Necrosis Factor alpha (TNF) is a pleiotropic pro-inflammatory cytokine with known vascular permeabilising activity. It is employed during isolated limb perfusion to enhance delivery of chemotherapeutic drugs into tumour tissue. The use of conditionally-replicating lytic viruses, so called 'oncolytic virotherapy', provides a new approach to cancer treatment that is currently limited by the low efficiency of extravasation of viral particles into tumours. We report here evidence that TNF significantly enhances the delivery of virus particles through the endothelial layer to allow access to tumour cells both in vitro and in vivo. Intravenous administration of TNF resulted in a 3- to 6-fold increase in EL4 tumour uptake of Evans Blue/Albumin, adenovirus and long-circulating polymer coated adenovirus. Interestingly, endothelial permeabilisation could be suppressed in vitro and in vivo by Y-27632, a Rho kinase inhibitor, without inhibiting viral infection. These data indicate that TNF can enhance the delivery of virus particles into tumours through a Rho A/Rho kinase dependent mechanism and may be a valuable strategy for increasing the delivery of oncolytic viruses and other therapeutic agents.

Adenovirus type 5 interactions with human blood cells may compromise systemic delivery.

Intravenous delivery of adenovirus vectors requires that the virus is not inactivated in the bloodstream. Serum neutralizing activity is well documented, but we show here that type 5 adenovirus also interacts with human blood cells. Over 90% of a typical virus dose binds to human (but not murine) erythrocytes ex vivo, and samples from a patient administered adenovirus in a clinical trial showed that over 98% of viral DNA in the blood was cell associated. In contrast, nearly all viral genomes in the murine bloodstream are free in the plasma. Adenovirus bound to human blood cells fails to infect A549 lung carcinoma cells, although dilution to below 1.7 x 10(7) blood cells/ml relieves this inhibition. Addition of blood cells can prevent infection by adenovirus that has been prebound to A549 cells. Adenovirus also associates with human neutrophils and monocytes ex vivo, particularly in the presence of autologous plasma, giving dose-dependent transgene expression in CD14-positive monocytes. Finally, although plasma with a high neutralizing titer (defined on A549 cells) inhibits monocyte infection, weakly neutralizing plasma can actually enhance monocyte transduction. This may increase antigen presentation following intravenous injection, while blood cell binding may both decrease access of the virus to extravascular targets and inhibit infection of cells to which the virus does gain access.

Inhibition of metalloproteinase cleavage enhances the cytotoxicity of Fas ligand.

The Fas ligand (FasL)/Fas receptor (CD95) pathway is an important mediator of apoptosis in the immune system and can also mediate cancer cell death. Soluble FasL (sFasL), shed from the membrane-bound form of the molecule by a putative metalloproteinase (MP), may function to locally regulate the activity of membrane-bound FasL. Using a replication-defective recombinant adenovirus-expressing FasL (RAdFasL), we identified a variable ability of different carcinoma cells to respond to FasL-induced cytotoxicity and to shed sFasL. Blockade of FasL cleavage with an MP inhibitor significantly enhanced RAdFasL-induced apoptosis suggesting that sFasL may antagonize the effect of membrane-bound FasL. In support of this concept, a recombinant adenovirus expressing a noncleavable form of FasL (RAdD4) was found to be a potent inducer of apoptosis even at very low virus doses. Our results highlight the therapeutic potential of noncleavable FasL as an antitumor agent and emphasize the important role of MP via the production of sFasL in regulating the response of the Fas pathway. Moreover, these findings have general implications for the therapeutic exploitation of TNF family ligands and for the possible impact of MP-based therapies on the normal physiology of Fas/TNF pathways.