Glycidyl-methacrylate-based electrospun mats and catalytic silver nanoparticles

P(AN-GMA) and PGMA fibers coated with monodisperse silver nanoparticles have been prepared by a combination of electrospinning and electroless plating. The morphology of the electrospun fibers remains unchanged after surface hydrazination. Oxidation of hydrazine in an ammoniacal solution of AgNO3 reduces and deposits silver atoms along the fiber surface, which then coalesce to Ag particles. The size of the silver nanoparticles is varied between 20-60 nm. Since the density of the active sites for silver reduction is lower in P(AN-GAAA), a smaller particle size could be obtained. The catalytic activity of the silver nanoparticles has been confirmed

Immune-mediated loss of transgene expression from virally transduced brain cells is irreversible, mediated by IFNγ, perforin, and TNFα, and due to the elimination of transduced cells

The adaptive immune response to viral vectors reduces vector-mediated transgene expression from the brain. It is unknown, however, whether this loss is caused by functional downregulation of transgene expression or death of transduced cells. Herein, we demonstrate that during the elimination of transgene expression, the brain becomes infiltrated with CD4 and CD8 T cells and that these T cells are necessary for transgene elimination. Further, the loss of transgene-expressing brain cells fails to occur in the absence of IFNγ, perforin, and TNFα receptor. Two methods to induce severe immune suppression in immunized animals also fail to restitute transgene expression, demonstrating the irreversibility of this process. The need for cytotoxic molecules and the irreversibility of the reduction in transgene expression suggested to us that elimination of transduced cells is responsible for the loss of transgene expression. A new experimental paradigm that discriminates between downregulation of transgene expression and the elimination of transduced cells demonstrates that transduced cells are lost from the brain upon the induction of a specific antiviral immune response. We conclude that the anti-adenoviral immune response reduces transgene expression in the brain through loss of transduced cellsFil: Zirger, Jeffrey M.. Cedars Sinai Medical Center; Estados Unidos. University of California at Los Angeles. School of Medicine; Estados UnidosFil: Puntel, Mariana. University of California at Los Angeles. School of Medicine; Estados Unidos. Cedars Sinai Medical Center; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bergeron, Josee. Cedars Sinai Medical Center; Estados Unidos. University of California at Los Angeles. School of Medicine; Estados UnidosFil: Wibowo, Mia. University of California at Los Angeles. School of Medicine; Estados Unidos. Cedars Sinai Medical Center; Estados UnidosFil: Moridzadeh, Rameen. University of California at Los Angeles. School of Medicine; Estados Unidos. Cedars Sinai Medical Center; Estados UnidosFil: Bondale, Niyati. Cedars Sinai Medical Center; Estados Unidos. University of California at Los Angeles. School of Medicine; Estados UnidosFil: Barcia, Carlos. Cedars Sinai Medical Center; Estados Unidos. University of California at Los Angeles. School of Medicine; Estados UnidosFil: Kroeger, Kurt M.. University of California at Los Angeles. School of Medicine; Estados Unidos. Cedars Sinai Medical Center; Estados UnidosFil: Liu, Chunyan. University of California at Los Angeles. School of Medicine; Estados Unidos. Cedars Sinai Medical Center; Estados UnidosFil: Castro, Maria Graciela. University of California at Los Angeles. School of Medicine; Estados Unidos. Cedars Sinai Medical Center; Estados Unidos. University of Michigan; Estados UnidosFil: Lowenstein, Pedro R.. Cedars Sinai Medical Center; Estados Unidos. University of California at Los Angeles. School of Medicine; Estados Unidos. University of Michigan; Estados Unido

Efficient recombinase-mediated cassette exchange at the AAVS1 locus in human embryonic stem cells using baculoviral vectors

Insertion of a transgene into a defined genomic locus in human embryonic stem cells (hESCs) is crucial in preventing random integration-induced insertional mutagenesis, and can possibly enable persistent transgene expression during hESC expansion and in their differentiated progenies. Here, we employed homologous recombination in hESCs to introduce heterospecific loxP sites into the AAVS1 locus, a site with an open chromatin structure that allows averting transgene silencing phenomena. We then performed Cre recombinase mediated cassette exchange using baculoviral vectors to insert a transgene into the modified AAVS1 locus. Targeting efficiency in the master hESC line with the loxP-docking sites was up to 100%. Expression of the inserted transgene lasted for at least 20 passages during hESC expansion and was retained in differentiated cells derived from the genetically modified hESCs. Thus, this study demonstrates the feasibility of genetic manipulation at the AAVS1 locus with homologous recombination and using viral transduction in hESCs to facilitate recombinase-mediated cassette exchange. The method developed will be useful for repeated gene targeting at a defined locus of the hESC genome

Levetiracetam-loaded biodegradable polymer implants in the tetanus toxin model of temporal lobe epilepsy in rats

Approximately one-third of people with epilepsy receive insufficient benefit from currently available anticonvulsant medication, and some evidence suggests that this may be due to a lack of effective penetration into brain parenchyma. The current study investigated the ability of biodegradable polymer implants loaded with levetiracetam to ameliorate seizures following implantation above the motor cortex in the tetanus toxin model of temporal lobe epilepsy in rats. The implants led to significantly shorter seizures and a trend towards fewer seizures for up to 1 week. The results of this study indicate that drug-eluting polymer implants represent a promising evolving treatment option for intractable epilepsy. Future research is warranted to investigate issues of device longevity and implantation site

Transduction of Brain Dopamine Neurons by Adenoviral Vectors Is Modulated by CAR Expression: Rationale for Tropism Modified Vectors in PD Gene Therapy

Gene-based therapy is a new paradigm for the treatment of Parkinson disease (PD) and offers considerable promise for precise targeting and flexibility to impact multiple pathobiological processes for which small molecule agents are not available. Some success has been achieved utilizing adeno-associated virus for this approach, but it is likely that the characteristics of this vector system will ultimately create barriers to progress in clinical therapy. Adenovirus (Ad) vector overcomes limitations in payload size and targeting. The cellular tropism of Ad serotype 5 (Ad5)-based vectors is regulated by the Ad attachment protein binding to its primary cellular receptor, the coxsackie and adenovirus receptor (CAR). Many clinically relevant tissues are refractory to Ad5 infection due to negligible CAR levels but can be targeted by tropism-modified, CAR-independent forms of Ad. Our objective was to evaluate the role of CAR protein in transduction of dopamine (DA) neurons in vivo.Ad5 was delivered to the substantia nigra (SN) in wild type (wt) and CAR transgenic animals. Cellular tropism was assessed by immunohistochemistry (IHC) in the SN and striatal terminals. CAR expression was assessed by western blot and IHC. We found in wt animals, Ad5 results in robust transgene expression in astrocytes and other non-neuronal cells but poor infection of DA neurons. In contrast, in transgenic animals, Ad5 infects SNc neurons resulting in expression of transduced protein in their striatal terminals. Western blot showed low CAR expression in the ventral midbrain of wt animals compared to transgenic animals. Interestingly, hCAR protein localizes with markers of post-synaptic structures, suggesting synapses are the point of entry into dopaminergic neurons in transgenic animals.These findings demonstrate that CAR deficiency limits infection of wild type DA neurons by Ad5 and provide a rationale for the development of tropism-modified, CAR-independent Ad-vectors for use in gene therapy of human PD

Designer Gene Delivery Vectors: Molecular Engineering and Evolution of Adeno-Associated Viral Vectors for Enhanced Gene Transfer

Gene delivery vectors based on adeno-associated virus (AAV) are highly promising due to several desirable features of this parent virus, including a lack of pathogenicity, efficient infection of dividing and non-dividing cells, and sustained maintenance of the viral genome. However, several problems should be addressed to enhance the utility of AAV vectors, particularly those based on AAV2, the best characterized AAV serotype. First, altering viral tropism would be advantageous for broadening its utility in various tissue or cell types. In response to this need, vector pseudotyping, mosaic capsids, and targeting ligand insertion into the capsid have shown promise for altering AAV specificity. In addition, library selection and directed evolution have recently emerged as promising approaches to modulate AAV tropism despite limited knowledge of viral structure–function relationships. Second, pre-existing immunity to AAV must be addressed for successful clinical application of AAV vectors. “Shielding” polymers, site-directed mutagenesis, and alternative AAV serotypes have shown success in avoiding immune neutralization. Furthermore, directed evolution of the AAV capsid is a high throughput approach that has yielded vectors with substantial resistance to neutralizing antibodies. Molecular engineering and directed evolution of AAV vectors therefore offer promise for generating ‘designer’ gene delivery vectors with enhanced properties

Advances in the treatment of prolactinomas

Prolactinomas account for approximately 40% of all pituitary adenomas and are an important cause of hypogonadism and infertility. The ultimate goal of therapy for prolactinomas is restoration or achievement of eugonadism through the normalization of hyperprolactinemia and control of tumor mass. Medical therapy with dopamine agonists is highly effective in the majority of cases and represents the mainstay of therapy. Recent data indicating successful withdrawal of these agents in a subset of patients challenge the previously held concept that medical therapy is a lifelong requirement. Complicated situations, such as those encountered in resistance to dopamine agonists, pregnancy, and giant or malignant prolactinomas, may require multimodal therapy involving surgery, radiotherapy, or both. Progress in elucidating the mechanisms underlying the pathogenesis of prolactinomas may enable future development of novel molecular therapies for treatment-resistant cases. This review provides a critical analysis of the efficacy and safety of the various modes of therapy available for the treatment of patients with prolactinomas with an emphasis on challenging situations, a discussion of the data regarding withdrawal of medical therapy, and a foreshadowing of novel approaches to therapy that may become available in the future

Gene therapy strategies for intracranial tumours: glioma and pituitary adenomas

Intracranial tumours such as brain gliomas and pituitary adenomas pose a challenging area of research for the development of gene therapy strategies, both from the point of view of the severity of the diseases, to the physiological implication of gene delivery into the central nervous system and pituitary gland. On the one hand, brain gliomas are very malignant tumours, with a life expectancy of six months to a year at the most after the time of diagnosis, in spite of advances in treatment modalities which involve chemotherapy, surgery and radiotherapy. Gene therapy for these tumours is therefore a very attractive therapeutic modality which due to the severity of the disease is already in clinical trials. On the other hand, pituitary tumours are usually benign, and in most cases, treatment is successful. Nevertheless, there are some instances, especially with the macroadenomas and some invasive tumours in which treatment fails. Gene therapy strategies for these adenomas therefore needs to progress substantially in terms of safety, adverse side effects and physiological impact on the normal pituitary gland before clinical implementation.In this paper, we will review gene delivery systems both viral and non-viral and several therapeutic strategies which could be implemented for the treatment of these diseases. These include cytotoxic approaches both conditional and direct, immune-stimulatory strategies, anti-angiogenic strategies and approaches which harness pro-apoptotic and tumour suppressor gene targets. We will also review the models which are currently available in which these gene therapy strategies can be tested experimentally.This new therapeutic modality holds enormous promise, but we still need substantial improvements both from the delivery, efficacy and safety stand points before it can become a clinical reality

Perceived risk of colorectal and breast cancers among women who are overweight or with obesity

Many overweight women or women with obesity do not acknowledge their high weight status and may be unaware of their elevated cancer risk. We explored the relationship between weight status and women's perceived risk of colorectal (CRC) and breast cancers, overall and by race/ethnicity, in a nationally representative sample.Data was combined from NHIS 2005, 2010, and 2015 sample adult questionnaires and cancer control supplements. The analytic sample included females aged 18 years and over without reported history of cancer diagnosis. Multivariable logistic regression was performed and adjusted estimates for perceived risk of CRC and breast cancers were examined, stratified by body mass index and race/ethnicity. Data were reported using predicted marginal risk ratio (PMR).Colorectal cancer risk perception remained lowest among Non-Hispanic (NH) Black women regardless of weight status (PMR = 0.53 obesity, 0.65 overweight, 0.55 normal) compared to NH White women after adjustment for all covariates. Hispanic women who were overweight or had obesity also saw themselves at lower risk of CRC compared to NH White women, however these findings were statistically insignificant. Breast cancer risk perception also remained low for NH Blacks and Hispanics at any weight compared with NH Whites.Greater effort is needed to develop, disseminate, and widely adopt or institutionalize multilevel weight management interventions and programs. These programs increase awareness of excess weight as a risk factor for cancer and empower women in diverse communities to achieve and maintain a healthy weight by adopting healthy behaviors related to nutrition and physical activity. Keywords: BMI, Cancer screening, Obesity, Overweight, Perceived ris