Armoring CRAds with p21/Waf-1 shRNAs: the next generation of oncolytic adenoviruses

Conditionally replicating adenoviruses (CRAds) represent a promising modality for the treatment of neoplastic diseases, including Prostate Cancer. Selectively replicating viruses can be generated by placing a tissue or cancer-specific promoter upstream of one or more of the viral genes required for replication (for example, E1A, E1B). We have previously reported multiple cellular processes that can attenuate viral replication, which in turn compromises viral oncolysis and tumor kill. In this study, we investigated the importance of the cyclin-dependent kinase inhibitor p21/Waf-1, on viral replication and tumor growth. To our knowledge, this is the first report describing the importance of p21/Waf-1shRNA on the induction of an androgen responsive element (ARE) based promoter driving the E1A gene. As a proof of concept, the study emphasizes the use of RNA interference technology to overcome promoter weaknesses for tissue-specific oncolytic viruses, as well as the cellular inhibitor pathways on viral life cycle. Using RNA interference against p21/Waf-1, we were able to show an increase in viral replication and viral oncolysis of prostate cancer cells. Similarly, CRAd viruses that carry p21/Waf-1 shRNA (Ad5-RV004.21) were able to prevent tumor outgrowth that resulted in a marked increase in the mean survival time of tumor-bearing mice compared with CRAd without p21/Waf-1 shRNA (Ad5-RV004). In studies combining Ad5-RV004.21 with Adriamycin, a suprar-additive effect was observed only in CRAds that harbor shRNA against p21/Waf-1. Taken together, these findings of enhanced viral replication in prostate cancer cells by using RNA interference against the cdk inhibitor p21/Waf-1 have significant implications in the development of prostate-specific CRAd therapies.

Pharmacokinetics of intravenous ceftiofur sodium and concentration in body fluids of foals

The objectives of this study were to determine pharmacokinetics of intravenous (i.v.) ceftiofur in foals, to compare ultra-high performance liquid chromatography tandem mass spectometry (UPLC-MS/MS) and microbiologic assay for the measurement of ceftiofur concentrations, and to determine the minimum inhibitory concentration (MIC) of ceftiofur against common equine bacterial pathogens. In a cross-over design, ceftiofur sodium was administered i.v. to six foals (1-2 days-of-age and 4-5 weeks-of-age) at dosages of 5 and 10 mg/kg. Subsequently, five doses of ceftiofur were administered i.v. to six additional foals between 1 and 5 days of age at a dose of 5 mg/kg q 12 h. Concentrations of desfuroylceftiofur acetamide (DCA), the acetamide derivative of ceftiofur and desfuroylceftiofur-related metabolites were measured in plasma, synovial fluid, urine, and CSF by use of UPLC-MS/MS. A microbiologic assay was used to measure ceftiofur activity for a subset of plasma samples. Following i.v. administration of ceftiofur at a dose of 5 mg/kg to 1-2 day-old foals, DCA had a t(1/2) of 7.8 +/- 0.1 h, a body clearance of 74.4 +/- 8.4 mL/h/kg, and an apparent volume of distribution of 0.83 +/- 0.09 L/kg. After multiple i.v. doses at 5 mg/kg, DCA concentrations in CSF were significantly lower than concurrent plasma concentrations. Ceftiofur activity using a microbiologic assay significantly underestimated plasma concentrations of DCA. The MIC of ceftiofur required to inhibit growth of 90% of isolates of Escherichia coli, Pasteurella spp, Klebsiella spp, and beta-hemolytic streptococci was <0.5 microg/mL. Intravenous administration of ceftiofur sodium at the rate of 5 mg/kg every 12 h would provide sufficient coverage for the treatment of susceptible bacterial isolates.

Cunninghamella Bertholletiae Infection (Mucormycosis) in a Patient with Acute T-cell Lymphoblastic Leukemia

Cunninghamella spp. are unusual opportunistic pathogens that have been identified with increased frequency in immunocompromised patients. Clinical infection by this fungus is almost always devastating and usually fatal. Infections with this group of organisms have been seen most frequently in patients with hematological malignancy. Here we report the case of a patient with acute leukemia who developed multiorganic failure as a consequence of hematological dissemination by Cunninghamella bertholletiae. The case highlights the mortality associated with this fungal infection in immunocompromised patients, confirms the risk factors associated with non-candida fungal infections and shows a clinical presentation mimicking myocardial infarct and cerebrovascular stroke.

Epidemiology of tuberculosis in the Americas: the Stop TB strategy and the millennium development goals

BACKGROUND

Tuberculosis (TB), a preventable and curable disease, remains a major public health threat in the poorest regions of the Americas. The DOTS strategy was implemented to control TB in the region in 1993, and the new Stop TB strategy, emphasizing high-quality DOTS expansion, in 2006.

OBJECTIVES

To describe TB epidemiology in the region of the Americas from 1994 to 2005 and to analyze the progress made towards and prospects for achieving Goal 6 of the Millennium Development Goals (MDGs) by 2015.

METHODS

TB incidence, mortality and prevalence rates as well as DOTS coverage and DOTS treatment success rates were collated from the World Health Organization (WHO) databases from 1994 to 2005.

RESULTS

DOTS coverage and DOTS treatment success rates rose steadily from 1994 to 2005, with 88% of the population covered under DOTS by 2005, and an 80% success rate by the end of 2004. The TB incidence, prevalence and mortality rates have also decreased steadily from 1994 to date, but differ with respect to the various scenarios.

CONCLUSIONS

With the exception of some countries, further reduction in TB incidence, prevalence and deaths by 2015 is possible. Widespread implementation of DOTS should continue in order to meet WHO targets and attain the MDGs.

Mesenchymal stem cells and their use as cell replacement therapy and disease modelling tool

Mesenchymal stem cells (MSCs) from adult somatic tissues may differentiate in vitro and in vivo into multiple mesodermal tissues including bone, cartilage, adipose tissue, tendon, ligament or even muscle. MSCs preferentially home to damaged tissues where they exert their therapeutic potential. A striking feature of the MSCs is their low inherent immunogenicity as they induce little, if any, proliferation of allogeneic lymphocytes and antigen-presenting cells. Instead, MSCs appear to be immunosuppressive in vitro. Their multi-lineage differentiation potential coupled to their immuno-privileged properties is being exploited worldwide for both autologous and allo-geneic cell replacement strategies. Here, we introduce the readers to the biology of MSCs and the mechanisms underlying immune tolerance. We then outline potential cell replacement strategies and clinical applications based on the MSCs immunological properties. Ongoing clinical trials for graft-versus-host-disease, haematopoietic recovery after co-transplantation of MSCs along with haematopoietic stem cells and tissue repair are discussed. Finally, we review the emerging area based on the use of MSCs as a target cell subset for either spontaneous or induced neoplastic transformation and, for modelling non-haematological mesenchymal cancers such as sarcomas.

Diversity of soil yeasts isolated from South Victoria Land, Antarctica

Unicellular fungi, commonly referred to as yeasts, were found to be components of the culturable soil fungal population in Taylor Valley, Mt. Discovery, Wright Valley, and two mountain peaks of South Victoria Land, Antarctica. Samples were taken from sites spanning a diversity of soil habitats that were not directly associated with vertebrate activity. A large proportion of yeasts isolated in this study were basidiomycetous species (89%), of which 43% may represent undescribed species, demonstrating that culturable yeasts remain incompletely described in these polar desert soils. Cryptococcus species represented the most often isolated genus (33%) followed by Leucosporidium (22%). Principle component analysis and multiple linear regression using stepwise selection was used to model the relation between abiotic variables (principle component 1 and principle component 2 scores) and yeast biodiversity (the number of species present at a given site). These analyses identified soil pH and electrical conductivity as significant predictors of yeast biodiversity. Species-specific PCR primers were designed to rapidly discriminate among the Dioszegia and Leucosporidium species collected in this study.

Coincidence of a ductal pancreatic cyst and a gastric duplication cyst: a case report

We report a case of two abdominal cystic formations in an 18-month-old girl. Laparotomy was performed with surgical removal of both cysts. The cysts were connected by a fibrous bridge. Histology revealed a gastric duplication cyst and a ductal pancreatic cyst originating from an aberrant pancreatic lobe. No fistula was found either to the alimentary tract or in either of the cysts. The clinical picture and treatment are described and compared to findings in the literature.