A Simplified Geometric Model to Predict Nasal Spray Deposition in Children and Adults

A mathematical approach was developed to estimate spray deposition patterns in the nasal cavity based on the geometric relationships between the emitted spray plume and the anatomical dimensions of the nasal valve region of the nasal cavity. Spray plumes were assumed to be spherical cones and the nasal valve region was approximated as an ellipse. The effect of spray plume angle (15–85°) on the fraction of the spray able to pass through the nasal valve (deposition fraction) was tested for a variety of nasal valve (ellipse) shapes and cross-sectional areas based on measured dimensions from pediatric and adult nasal cavities. The effect of the distances between the tip of the nasal spray device and the nasal valve (0.2–1.9 cm) on the deposition fraction was also tested. Simulation results show that (1) decreasing spray plume angles resulted in higher deposition fractions, (2) deposition fraction was inversely proportional to the spray distance and the nasal valve (ellipse) major/minor axis ratio, and (3) for fixed major/minor axis ratios, improved deposition occurred with larger nasal valve cross-sectional areas. For a typical adult nasal valve, plume angles of less than 40° emitted from a distance of 1 cm resulted depositions greater than 90% within the main nasal cavity, whereas for a 12-year-old child, only the most narrow plume angles (<?20°) administered resulted in significant deposition beyond the nasal valve.     

Photostability Issues in Pharmaceutical Dosage Forms and Photostabilization

Photodegradation is one of the major pathways of the degradation of drugs. Some therapeutic agents and excipients are highly sensitive to light and undergo significant degradation, challenging the quality and the stability of the final product. The adequate knowledge of photodegradation mechanisms and kinetics of photosensitive therapeutic entities or excipients is a pivotal aspect in the product development phase. Hence, various pharmaceutical regulatory agencies, across the world, mandated the industries to assess the photodegradation of pharmaceutical products from manufacturing stage till storage, as per the guidelines given in the International Conference on Harmonization (ICH). Recently, numerous formulation and/or manufacturing strategies has been investigated for preventing the photodegradation and enhancing the photostability of photolabile components in the pharmaceutical dosage forms. The primary focus of this review is to discuss various photodegradation mechanisms, rate kinetics, and the factors that influence the rate of photodegradation. We also discuss light-induced degradation of photosensitive lipids and polymers. We conclude with a brief note on different approaches to improve the photostability of photosensitive products.     

Adaptive response and the bystander effect induced by radiation in C3H 10T(1/2) cells in culture.

This paper discusses two phenomena of importance at low doses that have an impact on the shape of the dose-response relationship. First, there is the bystander effect, the term used to describe the biological effects observed in cells that are not themselves traversed by a charged particle, but are neighbors of cells that are; this exaggerates the effect of small doses of radiation. Second, there is the adaptive response, whereby exposure to a low level of DNA stress renders cells resistant to a subsequent exposure; this reduces the effect of low doses of radiation. The present work was undertaken to assess the relative importance of the adaptive response and the bystander effect induced by radiation in C3H 10T(1/2) cells in culture. When the single-cell microbeam delivered from 1 to 12 alpha particles through the nuclei of 10% of C3H 10T(1/2) cells, more cells were inactivated than were actually traversed by alpha particles. The magnitude of this bystander effect increased with the number of particles per cell. An adaptive dose of 2 cGy of gamma rays, delivered 6 h beforehand, canceled out about half of the bystander effect produced by the alpha particles.     

The mouse Wnt/PCP protein Vangl2 is necessary for migration of facial branchiomotor neurons, and functions independently of Dishevelled

During development, facial branchiomotor (FBM) neurons, which innervate muscles in the vertebrate head, migrate caudally and radially within the brainstem to form a motor nucleus at the pial surface. Several components of the Wnt/planar cell polarity (PCP) pathway, including the transmembrane protein Vangl2, regulate caudal migration of FBM neurons in zebrafish, but their roles in neuronal migration in mouse have not been investigated in detail. Therefore, we analyzed FBM neuron migration in mouse looptail (Lp) mutants, in which Vangl2 is inactivated. In Vangl2(Lp/+) and Vangl2(Lp/Lp) embryos, FBM neurons failed to migrate caudally from rhombomere (r) 4 into r6. Although caudal migration was largely blocked, many FBM neurons underwent normal radial migration to the pial surface of the neural tube. In addition, hindbrain patterning and FBM progenitor specification were intact, and FBM neurons did not transfate into other non-migratory neuron types, indicating a specific effect on caudal migration. Since loss-of-function in some zebrafish Wnt/PCP genes does not affect caudal migration of FBM neurons, we tested whether this was also the case in mouse. Embryos null for Ptk7, a regulator of PCP signaling, had severe defects in caudal migration of FBM neurons. However, FBM neurons migrated normally in Dishevelled (Dvl) 1/2 double mutants, and in zebrafish embryos with disrupted Dvl signaling, suggesting that Dvl function is essentially dispensable for FBM neuron caudal migration. Consistent with this, loss of Dvl2 function in Vangl2(Lp/+) embryos did not exacerbate the Vangl2(Lp/+) neuronal migration phenotype. These data indicate that caudal migration of FBM neurons is regulated by multiple components of the Wnt/PCP pathway, but, importantly, may not require Dishevelled function. Interestingly, genetic-interaction experiments suggest that rostral FBM neuron migration, which is normally suppressed, depends upon Dvl function.     

Biosynthetic process and strain improvement approaches for industrial penicillin production

Biotechnology Letters - Penicillins and cephalosporins are the most important class of beta (β) lactam antibiotics, accounting for 65% total antibiotic market. Penicillins are produced by...     

Ternary complexes of palladium (II) with levamisole and L-amino acids

The complexes of general formula [(LMS)2Pd(amino acid)]Cl with LMS = levamisole, and amino acid = L-alanine, L-phenylglycine, L-phenylalanine, L-valine, L-methionine, and L-proline, were synthesized by the interaction of [(LMS)2PdCl2] with the sodium salts of L-amino acids. The newly synthesized complexes are characterized by elemental analysis, conductivity, magnetic susceptibility, optical rotation measurements, and UV-Vis, IR and 13C NMR spectral data. Levamisole is coordinated to palladium via the N-7 nitrogen and the amino acids through the amino nitrogen and carboxylate oxygen, except for L-methionine which binds the metal via nitrogen and sulfur atoms. Optically active [(LMS)2Pd(amino acid)]Cl complexes are obtained when L-amino acids or D,L-amino acids are used for the synthesis of these complexes. L-Methionine and L-proline complexes induce new cell forms in Baker's yeast (Saccharomyces cerevisiae) cells.     

Interleukin 18 Coexpression during Respiratory Syncytial Virus Infection Results in Enhanced Disease Mediated by Natural Killer Cells

Respiratory syncytial virus (RSV) causes bronchiolitis, the main cause of infantile hospitalization. Immunity against reinfection is poor, and there is great interest in boosting vaccine responses using live vectors expressing host cytokines. We therefore constructed a recombinant RSV expressing murine interleukin 18 (RSV/IL-18), a cytokine capable of inducing strong antiviral immune responses. In vitro RSV/IL-18 replicated at wild-type levels and produced soluble IL-18. In naïve BALB/c mice, RSV/IL-18 infection significantly increased both IL-18 mRNA and protein and attenuated the peak viral load 3-fold. Despite a reduced viral load, RSV/IL-18 infection caused a biphasic weight loss at days 2 and 6 postinfection that was not seen in wild-type infection. Day 2 disease was associated with enhanced pulmonary natural killer (NK) cell numbers and activity and was prevented by NK cell depletion during infection; day 6 disease was correlated with CD8 T-cell recruitment and was enhanced by NK cell depletion. IL-18 expression during priming also enhanced RSV-specific antibody responses and T-cell responses on secondary RSV infection. Therefore, while IL-18 boosted antiviral immunity and reduced the viral load, its coexpression worsened disease. This is the first recombinant RSV with this property, and these are the first studies to demonstrate that NK cells can induce pathology during pulmonary viral infections.Human respiratory syncytial virus (RSV) is the major cause of infantile viral bronchiolitis worldwide (27). RSV infection results in lower respiratory tract illness (LRTI) in 25 to 40% of children, with 0.5 to 2% requiring hospitalization. Immunity against RSV is short-lived and incomplete, and reinfection with the same strain can occur regularly throughout life. In elderly persons, RSV causes morbidity and mortality that match those resulting from influenza A virus infection in those vaccinated against seasonal influenza; there is currently no RSV vaccine. The relative roles of the virus and the immune response in causing disease are much debated (9).The proinflammatory cytokine interleukin 18 (IL-18) is produced by a wide range of cells, including macrophages, neutrophils, and airway epithelial cells, and is a potent promoter of immune responses. It induces gamma interferon (IFN-γ) production from T cells without the requirement for T-cell receptor (TCR) engagement, an effect that is greatly enhanced by the presence of IL-12. Together, these cytokines enhance T helper cell type 1 (Th1) responses (15, 25, 32). IL-18 also directly promotes NK cell activation and proliferation and has been shown to drive antiviral immunity in a number of situations (18, 24, 26). In the presence of IL-12, IL-18 is also capable of preventing IgE production (34), but in the absence of IL-12 (or with an abundance of IL-2 or IL-4), it promotes the differentiation of Th2 cells and induces nonspecific IgE production (33, 35). Increased RSV titers are seen in IL-18 knockout mice (2), and polymorphisms in the IL-18 promoter are associated with increased risk of severe bronchiolitis (23).To enhance and redirect immune responses upon RSV infection, we inserted various cytokine genes into the RSV genome for coexpression during infection in vitro and in vivo (3-7, 13). In the present study, we used this technique to investigate whether the potent immune-modulating capacity of IL-18 could be used to boost virus-specific immunity as a vaccine candidate; in addition, we aimed to examine how IL-18 expression influenced lung immune responses and disease severity. We found that both innate and adaptive immune responses were boosted by the coexpression of IL-18 from a recombinant RSV during respiratory tract infection of BALB/c mice. This resulted in a reduced primary viral load and enhanced memory responses with enhanced immunity on secondary infection. Unfortunately IL-18 expression also enhanced illness during primary infection, characterized by weight loss and increased pulmonary cellular infiltration. The unexpected and novel pattern of enhanced disease was accompanied by the excess recruitment of NK cells and then CD8 cells into the airways and lungs. Further investigation of this effect led us to identify NK cells as critical mediators of early disease and determinants of later CD8 T-cell responses. These results show that boosting the responses that reduce the viral load can increase disease severity in RSV infection.     

Two-step protocol to incorporate cells in thermoresponsive hydrogels

One of the stumbling blocks in the formation of a thermoresponsive cell-hydrogel hybrid (TCH) is the efficient incorporation of cells in thermoresponsive hydrogels (TH) using traditional top-down (i.e., cells penetrate in the pre-set gels from top surface) approach. This approach is slow and tedious because the hydrogel needs to soak in the cells culture for a long time to allow cells to penetrate from the gel surface in to the bulk of the gel. In addition, cell incorporation into TH is difficult because elevated dissolution temperatures of gelators are detrimental to cell viability, whereas the highly viscous gel state that formed at ambient temperatures retards the penetration of cells. We propose a bottom-up approach (i.e., cells mixed prior to gel setting) using a novel two-step protocol. The first step is the rapid cooling of the agarose solution from its dissolution temperature (98 degrees C) to 37 degrees C and equilibrating for 3-4 min. The second step is the mixing of fibroblasts with the agarose solution and natural cooling to the room temperature to form the TCH. With this novel protocol, 90% of fibroblasts are found to be trapped in the cell-gel hybrid.