Optimization of Transdermal Drug Delivery by Hydrogel-Enhanced Sonophoresis

External-field mediated transdermal drug delivery is a new alternative to oral delivery and hypodermic injections. This method allows patients to receive treatments via a drug-infused patch applied to the skin and offers continuous release of drug for up to a week. It is also relatively inexpensive compared to regular treatments. In our design, ultrasound and an applied electric field are used to increase the rate of drug diffusion and propagation from the patch into and across the skin. Previous research has shown that the application of ultrasound results in higher rates of transdermal transport by increasing the permeability of the stratum corneum. This permeabilization can be so great that the patch or drug reservoir itself becomes the most significant barrier to the overall transdermal drug transport. An applied voltage has been shown to be capable of creating a driving force for transport that counteracts this effect. In this project, we combined the effects of applied voltage and ultrasound in order to model the transdermal transport of insulin from a methyl-cellulose hydrogel through the skin. Because the typical drug-delivery patch is circular, we modeled the problem in a 2Daxisymmetric geometry. Next, we determined the effects of intensity and voltage on the average insulin concentration in the skin. To do this, we conducted a sensitivity analysis by varying the applied voltages and intensities on the hydrogel and calculating the corresponding average insulin concentration in the skin at a specific time point. Finally, by using an objective function, we maximized the flux of insulin through the skin while minimizing patient discomfort. The iontophoretic and sonophoretic aspects of our model were validated individually through comparison with experimental data. We found that voltage and intensity from ultrasound combined provide the greatest increase in insulin transport through the skin. An intensity of 1 kW/m2 in conjunction with an applied voltage of -2 V resulted in the optimum insulin flux through the skin while maintaining minimal patient discomfort. The optimal intensity was found to be at the lower end of the range of experimentally and clinically utilized values. This suggests that higher intensities may contribute unnecessary heating without significantly enhancing insulin transport through the skin. Based on our optimization results, it can be seen that transdermal delivery of insulin through the skin is efficient when coupled with ultrasound and applied voltage. Our results show that with the application of sonophoresis and iontophoresis, insulin is effectively able to diffuse through the skin into the bloodstream. Our optimization also shows that this type of insulin delivery would cause minimal discomfort or skin damage. This suggests that transdermal delivery of insulin through the skin is a promising treatment for patients with diabetes

High-throughput vectors for efficient gene silencing in plants

A major challenge in the post-genome era of plant biology is to determine the functions of all genes in the plant genome. A straightforward approach to this problem is to reduce or knockout expression of a gene with the hope of seeing a phenotype that is suggestive of its function. Insertional mutagenesis is a useful tool for this type of study but is limited by gene redundancy, lethal knockouts, non-tagged mutants, and the inability to target the inserted element to a specific gene. The efficacy of gene silencing in plants using inverted-repeat transgene constructs that encode a hairpin RNA (hpRNA) has been demonstrated by a number of groups, and has several advantages over insertional mutagenesis. In this paper we describe two improved pHellsgate vectors that facilitate rapid generation of hpRNA-encoding constructs, pHellsgate 4 allows the production of an hpRNA construct in a single step from a single polymerase chain reaction product, while pHellsgate 8 requires a two-step process via an intermediate vector. We show that these vectors are effective at silencing three endogenous genes in Arabidopsis, FLOWERING LOCUS C, PHYTOENE DESATURASE and ETHYLENE INSENSITIVE 2. We also show that a construct of sequences from two genes silences both genes

Virus-like particles assemble in plants and bacteria expressing the coat protein gene of Indian peanut clump virus

cDNA copies of the coat protein (CP) gene of Indian peanut clump virus (IPCV)-H were introduced into cells of Nicotiana benthamiana or Escherichia coli by transformation with vectors based on pROKII or pET respectively. In both plant and bacterial cells, IPCV CP was expressed and assembled to form virus-like particles (VLP). In plant extracts, the smallest preponderant particle length was about 50 nm. Other abundant lengths were about 85 and about 120 nm. The commonest VLP length in bacterial extracts was about 30 nm. Many of the longer VLP appeared to comprise aggregates of shorter particles. The lengths of the supposed 'monomer' VLP corresponded approximately to those expected for encapsidated CP gene transcript RNA. Immunocapture RT-PCR, using primers designed to amplify the CP gene, confirmed that the VLP contained RNA encoding IPCV-H CP. The results show that encapsidation does not require the presence of the 5'-terminal untranslated sequence of the virus RNA and suggest that if there is an 'origin of assembly' motif or sequence, it lies within the CP gene. When transgenic plants expressing IPCV-H CP were inoculated with IPCV-L, a strain that is serologically distinct from IPCV-H, the virus particles that accumulated contained both types of CP

Virus-like particles assemble in plants and bacteria expressing the coat protein gene of Indian peanut clump virus

cDNA copies of the coat protein (CP) gene of Indian peanut clump virus (IPCV)-H were introduced into cells of Nicotiana benthamiana or Escherichia coli by transformation with vectors based on pROKII or pET respectively. In both plant and bacterial cells, IPCV CP was expressed and assembled to form virus-like particles (VLP). In plant extracts, the smallest preponderant particle length was about 50 nm. Other abundant lengths were about 85 and about 120 nm. The commonest VLP length in bacterial extracts was about 30 nm. Many of the longer VLP appeared to comprise aggregates of shorter particles. The lengths of the supposed 'monomer' VLP corresponded approximately to those expected for encapsidated CP gene transcript RNA. Immunocapture RT-PCR, using primers designed to amplify the CP gene, confirmed that the VLP contained RNA encoding IPCV-H CP. The results show that encapsidation does not require the presence of the 5'-terminal untranslated sequence of the virus RNA and suggest that if there is an 'origin of assembly' motif or sequence, it lies within the CP gene. When transgenic plants expressing IPCV-H CP were inoculated with IPCV-L, a strain that is serologically distinct from IPCV-H, the virus particles that accumulated contained both types of CP

Phenylpropanoid compounds and disease resistance in transgenic tobacco with altered expression of L-phenylalanine ammonia-lyase

Article on phenylpropanoid compounds and disease resistance in transgenic tobacco with altered expression of L-phenylalanine ammonia-lyase

Construct design for efficient, effective and high-throughput gene silencing in plants

Post-transcriptional silencing of plant genes using anti-sense or co-suppression constructs usually results in only a modest proportion of silenced individuals. Recent work has demonstrated the potential for constructs encoding self-complementary 'hairpin' RNA (hpRNA) to efficiently silence genes. In this study we examine design rules for efficient gene silencing, in terms of both the proportion of independent transgenic plants showing silencing, and the degree of silencing. Using hpRNA constructs containing sense/anti-sense arms ranging from 98 to 853 nt gave efficient silencing in a wide range of plant species, and inclusion of an intron in these constructs had a consistently enhancing effect. Intron-containing constructs (ihpRNA) generally gave 90-100% of independent transgenic plants showing silencing. The degree of silencing with these constructs was much greater than that obtained using either co-suppression or anti-sense constructs. We have made a generic vector, pHANNIBAL, that allows a simple, single PCR product from a gene of interest to be easily converted into a highly effective ihpRNA silencing construct. We have also created a high-throughput vector, pHELLSGATE, that should facilitate the cloning of gene libraries or large numbers of defined genes, such as those in EST collections, using an in vitro recombinase system. This system may facilitate the large-scale determination and discovery of plant gene functions in the same way as RNAi is being used to examine gene function in Caenorhabditis elegans

Candidate driver genes involved in genome maintenance and DNA repair in Sézary syndrome

Key Points Aberrations in genome maintenance and DNA repair genes including POT1 occur at a high frequency in Sézary syndrome. Candidate driver genes and affected pathways in Sézary syndrome show extensive heterogeneity but overlap with other mature T-cell lymphomas.</jats:p

Candidate driver genes involved in genome maintenance and DNA repair in Sézary syndrome

© 2014 The Author 2014. Published by Oxford University Press. All rights reserved. In the present contribution, we address the idea that income inequality can 'get under the skin' and worsen the symptoms of depression. We investigate whether this effect can be explained by country differences in the average coping resources citizens have at their disposal, as well as the average extent to which they engage in social comparisons. In addition, we examine whether coping resources can protect individuals from the detrimental effect of inequality and whether the effect of inequality varies according to socio-economic (SES) positions. We use multilevel techniques on a sample of 43,824 respondents collected by the European Social Survey (ESS) 2006/2007 in 23 European countries and find that individuals in countries with greater income inequalities report more depressive symptoms. Although social comparisons are associated with more depressive symptoms, they do not explain the effect of inequality and neither do coping resources. However, we do find that coping resources can protect against the stress of living in a society with high income inequality. Our results provide some support for the idea that inequality is most corrosive to the mental health of the people in the middle of the income hierarchy.status: publishe