Viability Reagent, PrestoBlue, in Comparison With Other Available Reagents, Utilized in Cytotoxicity and Antimicrobial Assays.

Viability Reagent, PrestoBlue, in Comparison with Other Available Reagents, Utilized in Cytotoxicity and Antimicrobial Assays.

Int J Microbiol. 2013; 2013: 420601
Lall N, Henley-Smith CJ, De Canha MN, Oosthuizen CB, Berrington D

This study compared different commercially available viability reagents. The growth indicator reagents include p-iodonitrotetrazolium violet (INT), PrestoBlue, and Alamar Blue which were used for antimicrobial analysis against Streptococcus mutans, Prevotella intermedia, Propionibacterium acnes, and Mycobacterium tuberculosis. PrestoBlue and Alamar Blue are resazurin based reagents that resulted in a quick and easily distinguishable colour change that allowed for visual readings. INT and Sodium 3′-[1-(phenyl amino-carbonyl)-3,4-tetrazolium]-bis-[4-methoxy-6-nitro] benzene sulfonic acid hydrate (XTT) are tetrazolium based reagents which are converted to a formazan dye in the presence of metabolically active mitochondria enzyme. For cell viability analysis, reagents XTT and PrestoBlue were compared. PrestoBlue was able to clearly indicate the minimum inhibitory concentration (MIC) of various positive drug controls on various microbial strains. PrestoBlue was also a good indicator of the 50% inhibitory concentration (IC50) of positive drug controls on various cell lines. HubMed – drug


Collagen scaffolds in bone sialoprotein-mediated bone regeneration.

ScientificWorldJournal. 2013; 2013: 812718
Kruger TE, Miller AH, Wang J

Decades of research in bioengineering have resulted in the development of many types of 3-dimentional (3D) scaffolds for use as drug delivery systems (DDS) and for tissue regeneration. Scaffolds may be comprised of different natural fibers and synthetic polymers as well as ceramics in order to exert the most beneficial attributes including biocompatibility, biodegradability, structural integrity, cell infiltration and attachment, and neovascularization. Type I collagen scaffolds meet most of these criteria. In addition, type I collagen binds integrins through RGD and non-RGD sites which facilitates cell migration, attachment, and proliferation. Type I collagen scaffolds can be used for bone tissue repair when they are coated with osteogenic proteins such as bone morphogenic protein (BMP) and bone sialoprotein (BSP). BSP, a small integrin-binding ligand N-linked glycoprotein (SIBLING), has osteogenic properties and plays an essential role in bone formation. BSP also mediates mineral deposition, binds type I collagen with high affinity, and binds ? v ? 3 and ? v ? 5 integrins which mediate cell signaling. This paper reviews the emerging evidence demonstrating the efficacy of BSP-collagen scaffolds in bone regeneration. HubMed – drug


Costs of chronic obstructive pulmonary disease in relation to compliance with guidelines: a study in the primary care setting.

Ther Adv Respir Dis. 2013 May 7;
Miravitlles M, Sicras A, Crespo C, Cuesta M, Brosa M, Galera J, Lahoz R, Lleonart M, Riera MI

BACKGROUND: The aim of this study was to analyse the economic impact of nonadherence to the Global Initiative for Obstructive Lung Disease (GOLD) guidelines in patients with chronic obstructive pulmonary disease (COPD). METHODS: A retrospective analysis was carried out on a claim database. Patients aged at least 40 years with a diagnosis of COPD were eligible for this analysis. Demographics, medical data and use of resources were collected and direct and indirect costs were analysed (from January 2008 to June 2009). A probabilistic multivariate sensitivity analysis of avoided costs was carried out. All results are presented in annualized form and costs are expressed in Euros (2009). RESULTS: A total of 1365 patients were included, 79.5% were men. The mean age (±standard deviation) was 71.4 (±10.3) years, the mean forced expiratory volume in 1 s (FEV1) was 65.3% and they had a COPD history of 5.5 (±2.9) years. Patients were divided into an adherent group and a nonadherent group depending on whether therapeutic recommendations according to severity defined in the GOLD guidelines (2007) were followed. Patients in both groups were also classified as having stage II (FEV1 < 80% and < 50%) or stage III disease (FEV1 < 50% and ? 30%). The total annual drug cost per patient in the nonadherent group was €771.5 while it was only €426.4 for the adherent group. The average direct cost per patient per year in the nonadherent stage II group was €1465 (±971) and it rose to €2942 (±1918) for patients in the nonadherent group with stage III disease. The potential saving from the implementation of the GOLD guidelines in stage II COPD amounted to €758 per patient per year (68% saving on drug cost). In contrast, the cost for patients with stage III disease was higher in the adherent group versus the nonadherent group (€2468). CONCLUSIONS: The cost of COPD may vary according to compliance with the GOLD guidelines. The cost observed for patients with stage II disease is higher than expected in patients who adhere to treatment, but patients with stage III disease treated according to the GOLD guidelines had significantly higher treatment costs. HubMed – drug


Keto-Mycolic Acid-Dependent Pellicle Formation Confers Tolerance to Drug-Sensitive Mycobacterium tuberculosis.

MBio. 2013; 4(3):
Sambandan D, Dao DN, Weinrick BC, Vilchèze C, Gurcha SS, Ojha A, Kremer L, Besra GS, Hatfull GF, Jacobs WR

ABSTRACT The chronic nature of tuberculosis (TB), its requirement of long duration of treatment, its ability to evade immune intervention, and its propensity to relapse after drug treatment is discontinued are reminiscent of other chronic, biofilm-associated bacterial diseases. Historically, Mycobacterium tuberculosis was grown as a pellicle, a biofilm-like structure, at the liquid-air interface in a variety of synthetic media. Notably, the most widely administered human vaccine, BCG, is grown as a pellicle for vaccine production. However, the molecular requirements for this growth remain ill defined. Here, we demonstrate that keto-mycolic acids (keto-MA) are essential for pellicle growth, and mutants lacking in or depleted of this MA species are unable to form a pellicle. We investigated the role of the pellicle biofilm in the reduction of antibiotic sensitivity known as drug tolerance using the pellicle-defective ?mmaA4 mutant strain. We discovered that the ?mmaA4 mutant, which is both pellicle defective and highly sensitive to rifampicin (RIF) under planktonic growth, when incorporated within the wild-type pellicle biofilm, was protected from the bactericidal activity of RIF. The observation that growth within the M. tuberculosis pellicle biofilm can confer drug tolerance to a drug-hypersensitive strain suggests that identifying molecular requirements for pellicle growth could lead to development of novel interventions against mycobacterial infections. Our findings also suggest that a class of drugs that can disrupt M. tuberculosis biofilm formation, when used in conjunction with conventional antibiotics, has the potential to overcome drug tolerance. IMPORTANCE Two of the most important questions in tuberculosis (TB) research are (i) how does Mycobacterium tuberculosis persist in the human host for decades in the face of an active immune response and (ii) why does it take six months and four drugs to treat uncomplicated TB. Both these aspects of M. tuberculosis biology are reminiscent of infections caused by organisms capable of forming biofilms. M. tuberculosis is capable of growing as a biofilm-like structure called the pellicle. In this study, we demonstrate that a specific cell wall component, keto-mycolic acid, is essential for pellicle growth. We also demonstrate that a strain of M. tuberculosis that is both drug sensitive and pellicle defective exhibits commensal behavior and becomes drug tolerant by becoming part of a heterogeneous pellicle, a characteristic of multispecies biofilms. These observations could have important implications for identifying novel pathways for M. tuberculosis drug tolerance and the design of new modalities to rapidly treat TB. HubMed – drug