A lipidic delivery system of a triple vaccine adjuvant enhances mucosal immunity following nasal administration in mice

We previously developed an highly efficacious combination adjuvant comprised of innate defense regulator (IDR)-1002 peptide, poly(I:C) and polyphosphazene (TriAdj). Here we aimed to design and test the in vivo efficacy of a mucoadhesive nasal formulation of this adjuvant. To determine the physical properties of the formulation, the effect of addition of each individual component was characterised by gel electrophoresis and fluorescence quenching using rhodamine-poly(I:C). Cationic liposomes comprised of didodecyl dimethylammonium bromide (DDAB), dioleoyl phosphatidylethanolamine (DOPE) (50:50 or 75:25?mol:mol) and DDAB, L-α-phosphatidylcholine (egg PC) and DOPE (40:50:10?mol:mol:mol) were prepared by the thin-film extrusion method. The liposomes and TriAdj were combined by simple mixing. The formed complex (L-TriAdj) was characterized by dynamic light scattering, zeta potential, and mucin interactions. We found that IDR-1002 peptide, polyphosphazene and poly(I:C) self-assembled in solution forming an anionic complex. Exposure of RAW267.4 mouse macrophage cells to TriAdj alone vs. L-TriAdj indicated that DDAB/DOPE (50:50) and DDAB/EPC/cholesterol (40:50:10) complexation reduced TriAdj toxicity. Next, TriAdj-containing cationic liposomes were prepared at several molar ratios to determine optimal size, stability and desired positive charge. Transmission electron microscopy showed rearrangement of lipid structures on binding of liposomes to TriAdj and to mucin. Stable particles (<200?nm over 24?h) showed mucin binding of DDAB/DOPE?+?TriAdj was greater than DDAB/EPC/DOPE?+?TriAdj. To verify in vivo efficacy, mice were administered the DDAB/DOPE?+?TriAdj complex intranasally with ovalbumin as the antigen, and the immunogenic response was measured by ELISA (serum IgG1, IgG2a, IgA) and ELISpot assays (splenocyte IL-5, IFN-γ). Mice administered adjuvant showed a significantly greater immune response with L-TriAdj than TriAdj alone, with a dose-response proportionate to the triple adjuvant content, and an overall balanced Th1/Th2 immune response representing both systemic and mucosal immunity.     

Interplay of formulation and process methodology on the extent of nifedipine molecular dispersion in polymers

The aim of this study is to evaluate effects of formulation and process technology on drug molecular dispersibility in solid dispersions (SDs). Nifedipine solid dispersions with ethylcellulose (EC) and/or Eudragit RL (RL) prepared by co-precipitation, co-evaporation, and fusion methods were characterized with FTIR, DSC, and XRPD for the content of nifedipine as molecular dispersion, amorphous and/or crystalline suspensions. A method was developed based on regular solution and Flory-Huggins theories to calculate drug-polymer interaction parameter in solid dispersion systems. A synergic effect of RL and EC on nifedipine molecular dispersibility in solid dispersions was observed. Increasing RL/EC ratio resulted in a higher degree of drug-polymer interaction that thermodynamically favored molecular dispersion, which, however, was counteracted by a corresponding decrease in the matrix glass transition point that kinetically favored phase-separation. Process methodology was found to play an important role in the formation of amorphous SD. The ranking of technologies with respect to the extent of molecular dispersion from high to low is fusion > co-evaporation > co-precipitation, wherein the solidification rate of polymeric solution and non-solvent effects were linked to kinetic entrapment of drug molecules in polymeric networks. Since nifedipine molecular dispersibility in EC/RL polymer(s) is a result of interplay between thermodynamic and kinetic factors, nifedipine molecular dispersions prepared for this study are thermodynamically metastable systems. To explore those supersaturation systems for use in drug delivery of poorly water soluble drugs, it is critical to balance drug-polymer interactions and matrix glass transition point and to consider a process technology with a fast solidification rate during formulation and process development of amorphous SD.     

Cholesterol as a Potential Target for Castration-Resistant Prostate Cancer

Advanced prostate cancer (CaP) is often treated with androgen deprivation therapy (ADT). Despite high initial success rates of this therapy, recurrence of the cancer in a castration-resistant (CRPC) form is inevitable. It has been demonstrated that, despite the low levels of circulating androgens resulting from ADT, intratumoral androgen levels remain high and androgen receptor activation persists. Recently, it was discovered that de novo androgen synthesis is occurring within the tumor cells themselves, thus providing a potential mechanism for the high endogenous concentrations. A common upstream precursor in this steroidogenic pathway is cholesterol. For many decades, the breakdown of cholesterol homeostasis in cancer has been the focus of research, but this was largely to elucidate its involvement in maintaining membrane integrity and cell signaling. De novo steroidogenesis has provided a new avenue for cholesterol research and reinforces the importance of understanding the mechanisms that lead to the alterations in cholesterol regulation in the progression to CRPC. The findings to date suggest that cholesterol homeostasis is altered to support de novo androgen synthesis and appear to facilitate disease progression. We further propose that a better understanding of the link between cholesterol and de novo androgen synthesis in CaP progression may provide opportunities for novel therapeutic intervention, namely via eliminating sources of the precursor cholesterol. This review summarizes the implications of cholesterol dysregulation in CaP and particularly in the post-ADT castration-resistant state, as well as the potential implementation of novel therapies targeting these cholesterol sources.     

Myxobolus harikensis sp. nov. (Myxozoa: Myxobolidae) infecting fins of Cirrhina mrigala (Ham.)--an Indian major carp in Harike Wetland, Punjab (India)

During a study of myxosporean parasites of freshwater fishes of Punjab Wetlands, India, one new myxosporean species, Myxobolus harikensis sp. nov. was recorded from the caudal fin of Cirrhina mrigala (Ham.) (Cypriniformes: Cyprinidae). Plasmodia are small, white, spherical-to-rounded and are present on the caudal fin (in between the fin rays) having two to five spores per plasmodium. Spores of M. harikensis measure 10.1 × 8.5 μm in size, pyriform in valvular view and lenticular in sutural view pointing in the direction to the plane of slightly bent sutural line. Shell valves are thick, smooth, asymmetric and flattened at the sutural plane. Parietal folds are absent. Polar capsules are two, prominently unequal, broadly pyriform-to-rounded in shape and lie at different levels in the spore body cavity. The larger polar capsule is 5.0 × 3.1 μm in size, placed anteriorly on the sutural plane and opening to the exterior anteriolaterally. The smaller polar capsule measures 1.7 × 1.4 μm in size, placed posteriorly, perpendicular to the sutural plane and opening to the exterior mediolaterally. Spores of M. harikensis closely resembles to that of Myxobolus africanus in having polar capsules placed at different levels in the spore body cavity, however, are unique in having unequal polar capsules both discharging laterally.     

Indications for Tonsillectomy: Are We Documenting Them?

INTRODUCTION

Tonsillectomy is one of the most frequently performed operations in the UK. Documentation of the indications for tonsillectomy is vital, and should fulfil evidence-based guidelines where possible. We present a completed audit, evaluating the documentation of our department''s practice in meeting the recommendations made by the Scottish Intercollegiate Guideline Network (SIGN) on indications for tonsillectomy.

PATIENTS AND METHODS

A prospective audit of 100 children undergoing tonsillectomy for recurrent tonsillitis at a university hospital during two time periods: October 2007 to January 2008 and March to September 2008. Interventions including the production of posters and rubber stamps were agreed and implemented between the two audit periods.

RESULTS

Following the implementation of simple changes, significant improvements were seen in documentation relating to the SIGN guidelines for tonsillectomy. Overall, the number of children meeting all four SIGN criteria for tonsillectomy rose from 12% to 44% (χ² = 57.8; P < 0.001). Furthermore, a significant reduction was seen in the number of children below the age of 5 years undergoing tonsillectomy for recurrent tonsillitis (χ² = 14.66; P < 0.001).

CONCLUSIONS

With increasing scrutiny on tonsillectomy, it is important to ensure that the reasons for performing tonsillectomy are documented clearly and adhere to evidence-based guidance where possible. We have demonstrated that, with only simple and low-cost interventions, significant improvements in the documentation of tonsillectomy indications can be achieved.     

Vascular cytochrome P450 4A expression and 20-hydroxyeicosatetraenoic acid synthesis contribute to endothelial dysfunction in androgen-induced hypertension

Epidemiological evidence suggests a role for sex-dependent mechanisms in the pathophysiology of hypertension. It has been shown that 5alpha-dihydrotestosterone (DHT) administration (56 mg/kg of body weight per day IP for 14 days) increases blood pressure, cytochrome P450 4A expression, and 20-hydroxyeicosatetraenoic acid synthesis in rats. We examined whether increased vascular 20-hydroxyeicosatetraenoic acid synthesis underlies endothelial dysfunction and hypertension in DHT-treated male Sprague-Dawley rats by using HET0016, a selective cytochrome P450 4A inhibitor. Coadministration of HET0016 (10 mg/kg per day IP for 14 days) to DHT-treated rats markedly reduced DHT-induced interlobar arterial production of 20-hydroxyeicosatetraenoic acid (14.3+/-1.5 versus 1.5+/-0.5 ng/mg of protein per hour; P<0.05), superoxide anion (246+/-47 versus 31+/-8 cpm/microg of protein), and the levels of gp91-phox, p47-phox, and 3-nitrosylated proteins. Moreover, the maximal relaxing response to acetylcholine in phenylephrine-preconstricted renal interlobar arteries from DHT-treated rats (42.8+/-4.8%) significantly (P<0.05) increased in the presence of HET0016 (81.5+/-10.8%). Importantly, the administration of HET0016 negated DHT-induced hypertension; systolic blood pressure was reduced from 146+/-2 mm Hg in DHT-treated rats to 130+/-1 mm Hg (P<0.05). The results strongly implicate vascular cytochrome P450 4A-derived 20-hydroxyeicosatetraenoic acid in the development of androgen-induced endothelial dysfunction and hypertension.