Use of pharmaceutical nanotechnology for the treatment of leishmaniasis

Abstract INTRODUCTION: Leishmaniasis is a global public health concern. Currently available treatments are associated with considerable side effects. The use of nanotechnology has shown promise for improving efficacy and bioavailability and minimizing side effects. METHODS: This study investigated available literature, including patents and scientific articles, to identify advances in the use of nanotechnology for the treatment of leishmaniasis. RESULTS: Our findings revealed a stable number of patents and scientific articles published over the past five years. CONCLUSIONS: There is a need to intensify research on the use of nanotechnology for the treatment of leishmaniasis.

A novel dosage form for buccal administration of bupropion

Bupropion is an antidepressant used in the treatment of smoking. The purpose of this study was to prepare controlled-release hydrogel films for buccal administration of bupropion and investigate its physicochemical and cytotoxic properties. The films were prepared from ultrapure sodium carboxymethylcellulose, hydroxypropylmethylcellulose K4M, and medium-viscosity chitosan. Evaluation of film physicochemical characteristics was based on scanning electron microscopy, bupropion content, mechanical strength (burst strength, relaxation, resilience, and traction), and cytotoxicity. Bupropion content in bilayer films was 121 mg per 9 cm2. The presence of bupropion modified film mechanical strength, but did not compromise the use of this pharmaceutical form. As shown by the cytotoxicity results, films containing bupropion did not cause cellular damage. Bupropion administration in the form of hydrogel films is a potentially useful alternative in the treatment of smoking.

A bupropiona é um antidepressivo utilizado no tratamento do tabagismo. O objetivo deste trabalho foi a preparação de filmes hidrogelatinosos de liberação controlada para administração bucal de bupropiona. Os filmes foram preparados utilizando carboximetilcelulose sódica ultrapurificada, hidroxipropilmetilcelulose K4M e quitosana de média viscosidade. As características físico-químicas dos filmes foram avaliadas por microscopia eletrônica de varredura, teor de bupropiona, resistência mecânica (perfuração, relaxação, resiliência e tração) e citotoxicidade. Os resultados mostraram que os filmes em bicamada apresentaram teor de bupropiona de 121 mg por 9 cm2 de filme e que a bupropiona modifica a resistência mecânica dos filmes, sem, no entanto, inviabilizar o uso desta forma farmacêutica. Os estudos de citotoxicidade mostraram que as formulações dos filmes contendo bupropiona não causam dano celular. Este estudo mostrou que a bupropiona veiculada na forma de filme hidrogelatinoso pode ser uma alternativa útil no tratamento do tabagismo.

Vascular endothelial growth factor-A enhances indoleamine 2,3-dioxygenase expression by dendritic cells and subsequently impacts lymphocyte proliferation

Dendritic cells (DCs) are antigen (Ag)-presenting cells that activate and stimulate effective immune responses by T cells, but can also act as negative regulators of these responses and thus play important roles in immune regulation. Pro-angiogenic vascular endothelial growth factor (VEGF) has been shown to cause defective DC differentiation and maturation. Previous studies have demonstrated that the addition of VEGF to DC cultures renders these cells weak stimulators of Ag-specific T cells due to the inhibitory effects mediated by VEGF receptor 1 (VEGFR1) and/or VEGFR2 signalling. As the enzyme indoleamine 2,3-dioxygenase (IDO) is recognised as an important negative regulator of immune responses, this study aimed to investigate whether VEGF affects the expression of IDO by DCs and whether VEGF-matured DCs acquire a suppressor phenotype. Our results are the first to demonstrate that VEGF increases the expression and activity of IDO in DCs, which has a suppressive effect on Ag-specific and mitogen-stimulated lymphocyte proliferation. These mechanisms have broad implications for the study of immunological responses and tolerance under conditions as diverse as cancer, graft rejection and autoimmunity.

Analysis of in vivo absorption of didanosine tablets in male adult dogs by HPLC / 药物分析学报

Didanosine is an effective antiviral drug in untreated and antiretroviral therapy-experienced patients with Human Immunodeficiency Virus (HIV).An automated system using on-line solid extraction and High performance Liquid Chromatography (HPLC) with ultraviolet (UV) detection was developed and validated for pharmacokinetic analysis of didanosiae in dog plasma.Modifications were introduced on a previous methodology for simultaneous analysis of antiretroviral drugs in human plasma.Extraction was carried out on C18 cartridges,with high extraction yield as stationary phase,whereas mobile phase consisted of a mixture of 0.02 M potassium phosphate buffer,acetonitrile (KH2PO4:acetonitrile:96∶4,v/v) and 0.5％ (w/v) of heptane sulphonic acid.The pH was adjusted to 6.5 with triethylamine.All samples and standard solutions were chromatographed at 28℃.For an isocratic run,the flux was 1.0 mL/min,detection was at 250nm and injected volume was 20μL.The method was selective and linear for concentrations between 50 and 5000 ng/mL.Drug stability data ranged from 96％ to 98％,and limit of quantification was 25 ng/mL.Extraction yield was up to 95％.Drug stability in dog plasma was kept frozen at -20℃ for one month after thee freeze-thaw cycles,and for 24 h after processing in the auto sampler.Assay was successfully applied to measure didanosine concentrations in plasma dogs.

Preparation of gastro-resistant pellets containing chitosan microspheres for improvement of oral didanosine bioavailability / 药物分析学报

The purpose of this work was to introduce a new concept of coated pellets containing chitosan microspheres loaded with didadosine for oral administration,aiming at reducing the frequency of administration and improving the bioavailability by a suitable release profile.Chitosan microspheres were produced under fluidized bed,followed by extrusion and spheronization to obtain pellets with a mean diameter of about 1 mm.The pellets were then coated with Kollidon(R) VA64 and Kollicoat(R) MAE100P in water dispersion to depict a sustained release profile.Conventional hard gelatine capsules were loaded with these pellets and tested in vitro for their release profile of didadosine.Dissolution testing confirmed that chitosan microsphere pellets provides appropriate sustained release up to 2 h behavior for didanosine.

Avaliação da expressão de microRNAs em linhagens celulares de carcinoma epidermoide de cabeça e pescoço e em cultura primária de queratinócitos orais / Evaluation of microRNA expression in head and neck squamous cell carcinoma cell lines and in primary culture of oral keratinocytes

Objective: Functional in vitro studies are fundamental to understand the role of microRNAs, small non coding RNA molecules that function as post-transcriptional regulators, in cancer. The objective of this study was to determine the applicability of head and neck squamous cell carcinoma cell lines and human oral keratinocytes as models for functional studies on microRNAs previously identified as deregulated in head and neck squamous cell carcinomas. Methods: The expression level of four microRNAs was assessed in cell lines and in primary cultures of oral keratinocytes using specific real-time polymerase chain reactions. The identity of oral squamous cell carcinoma cell lines was confirmed by means of STR (short tandem repeats) profiling. The possible impact of feeder-layer gene expression in global microRNA expression results from keratinocyte primary culture was also evaluated. Results: Significant differences in microRNA gene expression were observed among squamous cell carcinoma cell lines, particularly among cells lines from distinct subsites, as well as between primary culture of human keratinocytes and immortalized keratinocyte cell lines. Conclusions: Primary cultures of human keratinocytes and diverse tumor cell lines are relatively easy to obtain. However, each cell model possesses a characteristic phenotype; whereas one may be useful for a specific study, it may be inappropriate for another. Therefore, it is imperative that suitable cell lines are cautiously selected for functional studies in cancer.

Objetivo: Estudos funcionais in vitro são essenciais para a compreensão do papel de microRNAs, pequenas moléculas de RNA que desempenham papel importante na regulação gênica, no câncer. Neste estudo, analisamos a viabilidade de linhagens celulares derivadas de carcinoma epidermoide de cabeça e pescoço, queratinócitos orais provenientes de culturas primárias e queratinócitos imortalizados, como modelos para estudos funcionais de microRNAs previamente identificados como desregulados nesse tipo de carcinoma. Métodos: Avaliamos a expressão de quatro microRNAs em linhagens celulares e em cultura primária de queratinócitos orais por meio de reações em cadeia da polimerase em tempo real específica. As linhagens celulares de carcinoma epidermoide de boca foram previamente caracterizadas quanto ao seu perfil de sequências de DNA do tipo STR (do inglês short tandem repeats ou repetições curtas em sequência) com o objetivo de confirmar a identidade da linhagem. Avaliamos ainda a possível influência da expressão gênica detectada na camada de sustentação usada no cultivo de queratinócitos no resultado global obtido. Resultados: Nossos resultados apontam diferenças significativas na expressão dos microRNAs entre linhagens celulares passíveis de serem utilizadas como modelos para estudos funcionais em carcinoma epidermoide de cabeça e pescoço. Ressaltam-se diferenças entre linhagens de carcinoma de língua e de faringe, bem como diferenças expressivas entre a linhagem de queratinócitos orais imortalizados e queratinócitos orais normais provenientes de culturas primárias. Conclusão: Culturas primárias de queratinócitos orais bem como linhagens tumorais são obtidas de forma relativamente simples. Entretanto, cada modelo celular possui características particulares que os tornam mais ou menos adequados para um determinado estudo. Conclui-se que a seleção cuidadosa das linhagens é fundamental para estudos funcionais sobre câncer.

Biomarkers in Parkinson Disease: global gene expression analysis in peripheral blood from patients with and without mutations in PARK2 and PARK8 / Biomarcadores na doença de Parkinson: avaliação da expressão gênica no sangue periférico de pacientes com e sem mutações nos genes PARK2 e PARK8

Objective: To evaluate the performance of gene expression analysis in the peripheral blood of Parkinson disease patients with different genetic profiles using microarray as a tool to identify possible diseases related biomarkers which could contribute to the elucidation of the pathological process, as well as be useful in diagnosis. Methods: Global gene expression analysis by means of DNA microarrays was performed in peripheral blood of Parkinson disease patients with previously identified mutations in PARK2 or PARK8 genes, Parkinson disease patients without known mutations in these genes and normal controls. Each group consisted of five individuals. Results: Global gene expression profiles were heterogeneous among patients and controls, and it was not possible to detect a consistent pattern between groups. However, analyzing genes with differential expression of p < 0.005 and fold change greater than or equal to 1.2, we were able to identify a small group of well-annotated genes. Conclusions: Despite the small sample size, the identification of differentially expressed genes suggests that the microarray technique may be useful in identifying potential biomarkers in the peripheral blood of Parkinson disease patients or in people at risk of developing the disease. This will be important once neuroprotective therapies become available, and may contribute to the identification of new pathways involved in the disease physiopathology. Results presented here should be further validated in larger groups of patients.

Objetivo: Avaliar a viabilidade da análise da expressão gênica por microarray no sangue periférico de pacientes com doença de Parkinson com diferentes perfis genéticos, para a identificação de marcadores que possam estar relacionados ao desenvolvimento da doença ou que possam se tornar úteis para o seu o diagnóstico. Métodos: Foram selecionados pacientes portadores de mutações nos genes PARK2 ou PARK8, além de parkinsonianos não-portadores dessas mutações e controles sadios, sendo cinco pessoas em cada grupo. A expressão gênica global foi analisada por microarray com RNA extraído do sangue periférico desses pacientes. Resultados: O perfil de expressão global apresentou grande heterogeneidade entre os pacientes, não sendo possível identificar um padrão diferencial entre os grupos. No entanto, utilizando como critérios de seleção p < 0,005 e fold-change maior ou igual a 1,2, observamos expressão diferencial de alguns genes específicos entre os diferentes grupos estudados. Conclusões: A detecção de expressão diferencial de alguns genes sugere que a técnica pode vir a ser útil na identificação de marcadores em sangue periférico que possam caracterizar pessoas com risco de desenvolver doença de Parkinson, o que será importante, uma vez que terapias neutroprotetoras se tornem disponíveis, bem como auxiliará na elucidação da fisiopatologia da doença, identificando novas vias de sinalização que possam estar comprometidas. Esses achados deverão ainda ser confirmados por novos estudos com ampliação das amostras e testes para validação dos genes identificados.