Analysis of human MDM4 variants in papillary thyroid carcinomas reveals new potential markers of cancer properties

A wild-type (wt) p53 gene characterizes thyroid tumors, except for the rare anaplastic histotype. Because p53 inactivation is a prerequisite for tumor development, alterations of p53 regulators represent an alternative way to impair p53 function. Indeed, murine double minute 2 (MDM2), the main p53 negative regulator, is overexpressed in many tumor histotypes including those of the thyroid. A new p53 regulator, MDM4 (a.k.a. MDMX or HDMX) an analog of MDM2, represents a new oncogene although its impact on tumor properties remains largely unexplored. We estimated levels of MDM2, MDM4, and its variants, MDM4-S (originally HDMX-S) and MDM4-211 (originally HDMX211), in a group of 57 papillary thyroid carcinomas (PTC), characterized by wt tumor protein 53, in comparison to matched contra-lateral lobe normal tissue. Further, we evaluated the association between expression levels of these genes and the histopathological features of tumors. Quantitative real-time polymerase chain reaction revealed a highly significant downregulation of MDM4 mRNA in tumor tissue compared to control tissue (P < 0.0001), a finding confirmed by western blot on a subset of 20 tissue pairs. Moreover, the tumor-to-normal ratio of MDM4 levels for each individual was significantly lower in late tumor stages, suggesting a specific downregulation of MDM4 expression with tumor progression. In comparison, MDM2 messenger RNA (mRNA) and protein levels were frequently upregulated with no correlation with MDM4 levels. Lastly, we frequently detected overexpression of MDM4-S mRNA and presence of the aberrant form, MDM4-211 in this tumor group. These findings indicate that MDM4 alterations are a frequent event in PTC. It is worthy to note that the significant downregulation of full-length MDM4 in PTC reveals a novel status of this factor in human cancer that counsels careful evaluation of its role in human tumorigenesis and of its potential as therapeutic target

Practical tools to identify short children born small-for-gestational-age eligible for rhGH treatment according to Italian regulation

Recombinant human growth hormone (rhGH) is an approved and effective treatment for short children born small for gestational age (SGA). Prevalence of children eligible for treatment as SGA is reported to be 1:1800. The latest data from the National Registry of Growth Hormone therapy (RNAOC) showed that the number of children treated with SGA indication is still small (prevalence 0.37/100,000) and these children are significantly less reported than those treated for growth hormone deficiency (GHD), although GHD prevalence is 1:4000-1:10,000. This means that many short children born SGA are still not properly identified, and therefore not treated with rhGH, or misdiagnosed as GHD. This article provides some practical tools for the identification of children eligible for rhGH treatment

LC Evaluation of In Vitro Release of AZT from Microemulsions

A reversed phase LC method was developed and validated to analyze the in vitro release of AZT from microemulsions. A mobile phase of acetonitrile:water (15:85) was used. The method validation showed good selectivity and linearity (r = 0.9993) for sample concentrations ranging from 0.6 to 100.0 mu g mL(-1). The RSD values (0.7-4.3%) and percentage recovery (88.1-109.8%) were within acceptable limits. The limit of detection (LOD) and limit of quantitation (LOQ) were found to be 0.012 and 0.041 mu g mL(-1). Quantitative analysis of the values obtained in the drug release assay indicates that the microemulsions used promote sustained release of AZT, which follows a Fickian diffusion mechanism.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Surfactant systems for nasal zidovudine delivery: structural, rheological and mucoadhesive properties

Objectives Zidovudine is the antiretroviral drug most frequently used for the treatment of AIDS. Although its effectiveness is recognized, it undergoes extensive first-pass metabolism and exhibits poor oral bioavailability. The nasal route is an option for enhanced therapeutic efficacy and to reduce the extent of the first-pass effect. There are some mechanisms that limit intranasal absorption, such as mucociliary clearance, which rapidly removes the formulation from the nasal cavity. To improve the nasal residence time of zidovudine on the nasal mucosa, we aimed to develop a mucoadhesive surfactant system for zidovudine nasal administration.Methods Systems composed of PPG-5-CETETH-20 as surfactant, oleic acid and water were characterized by polarized light microscopy, small-angle X-ray scattering and rheological measurements. Mucoadhesion was investigated by phase behaviour studies, rheological synergism and mucoadhesive strength determination.Key findings Results indicate that the original formulations were microemulsions that displayed phase transition to a lamellar phase when brought into contact with aqueous nasal simulated mucus. The phase transition was accompanied by an increase in system elasticity and, irrespective of phase behaviour, all the systems showed a good mucoadhesive force. Thus, a viscous and mucoadhesive liquid crystalline matrix could be formed when the formulations were in contact with simulated mucus, which may prolong the residence time of zidovudine in the nasal cavity.Conclusions These findings indicate a potentially useful system for nasal administration of zidovudine.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Contrast-enhanced ultrasound of pancreatic tumours

Indication/purpose: To review contrast-enhanced ultrasound features of the most common pancreatic tumours. Methods: Contrast-enhanced ultrasound (CEUS) can provide distinctive features of pancreatic tumours that are reported in the present paper, providing radiologic-pathological correlations and clarifying the main differential diagnosis. Conclusion: Contrast-enhanced ultrasound plays a well-established role in the evaluation of pancreatic tumours. When possible, CEUS should be always performed after the initial US diagnosis, in order to improve the accuracy of the first line examination

Beckwith-Wiedemann syndrome and twinning: case report and brief review of literature

Abstract Background Beckwith-Wiedemann syndrome (BWS, OMIM #130,650) is a pediatric overgrowth disorder involving a predisposition to tumor development. Although the clinical management of affected patients is well established, it is less clear how to handle with the cases of siblings of affected patients, since the prevalence of the condition in twins (1:1000) is ten times higher than in singletones (1:10000). Case presentation We report the case of a premature twin patient who during her follow-up develops a clinical phenotype compatible with BWS, genetically confirmed in blood. However, the methylation alteration characteristic of the condition was also found in the almost phenotypically normal sibling, making it challening her management. Conclusion Through our case report we highlight how the diagnosis of BWS can be made without any prenatal suspicion and we propose a review of the literature on how to manage siblings of affected patients in twinning situation

Development and In Vitro Evaluation of Surfactant Systems for Controlled Release of Zidovudine

The development of a controlled-release dosage form of zidovudine (AZT) is of crucial importance, in view of the pharmacokinetics of its toxic activity. A suitable drug delivery system could increase AZT bioavailability, reducing its dose-dependent side effects. In this study, systems composed of polyoxypropylene (5) polyoxyethylene (20) cetyl alcohol as surfactant (S), oleic acid as oil phase (O), and water (W) were developed, as possible AZT control release systems. They were characterized by polarized light microscopy (PLM), SAXS, and rheological analysis, followed by in vitro release assay. PLM and SAXS results indicated that the mixtures of S/O/W in the proportions 55/35/10 and 55/25/20 formed microemulsion (ME) systems, while 55/20/25 formed lamellar phase. The incorporation of AZT in these systems was greater than in water or oil; moreover. AZT incorporation did not significantly change the phase behavior of the mixtures. MEs behave as Newtonian fluids in flow rheological analysis and the lamellar phase as a pseudoplastic fluid. The release profile indicated that AZT could be released in a controlled manner, since an exponential pattern governs AZT diffusion, as demonstrated by the Weibull mathematical model. These systems are potential carriers for AZT and could have advantages over conventional pharmaceutical forms. (C) 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:2367-2374, 2010Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Preparation and Characterization of Chitosan Nanoparticles for Zidovudine Nasal Delivery

Zidovudine (AZT) is the antiretroviral drug most frequently used for the treatment of Acquired Immunodeficiency Syndrome. Its low oral bioavailability demands the development of innovative strategies to overcome the first pass metabolism. The nasal route is an option for enhanced therapeutic efficacy and to reduce the extent of the first-pass effect. In this article, AZT loaded chitosan nanoparticles were prepared by a modified ionotropic gelation method with sodium tripolyphosphate. The increase proportion of CS (NP1 10:01 (w/w)) promoted the formation of smaller nanoparticles (260 nm), while raising the proportion of TPP (NP2 5:1 w/w) increased the nanoparticles size (330 nm). The incorporation of AZT increased the nanoparticles size for both AZT-loaded nanoparticles AZT-loaded NP1 (406 nm) and AZT-loaded NP2 (425 nm). The incorporation of AZT into NP1 did not change the electrophoretic mobility, however, in AZT-loaded NP2 there was a significant increase. The positive surface of the nanoparticles is very important for the mucoadhesive properties due interaction with the sialic groups of the mucin. Nuclear resonance magnetic data showed that the higher concentration of chitosan in the nanoparticles favored the interaction of few phosphate units (pyrophosphate) by ionic interaction Scanning electron microscopy, revealed that the nanoparticles are nearly spherical shape with porous surface. The entrapment efficiency of AZT, was 17.58%+/- 1.48 and 11.02%+/- 2.05 for NP1 and NP2, respectively. The measurement of the mucoadhesion force using mucin discs and nasal tissue obtained values of NP1 = 2.12 and NP2 = 4.62. In vitro permeation study showed that the nanoparticles promoted an increase in the flux of the drug through the nasal mucosa. In view of these results, chitosan nanoparticles were found to be a promising approach for the incorporation of hydrophilic drugs and these results suggest that the CS-containing nanoparticles have great potential for nasal AZT administration.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Rheological, Mechanical and Adhesive Properties of Surfactant-Containing Systems Designed as a Potential Platform for Topical Drug Delivery

In the last few decades, nanotechnology has led to an advance in the development of topical drug delivery. Nanostructured drug delivery systems enable the compartmentalization of drugs in restricted environments, modifying the release profile and maintaining the required drug concentration for prolonged periods at the site of action and/or absorption. The development of nanostructured systems containing surfactants has evolved rapidly. Mixtures of surfactant, oil and water can self-associate to form structures, such as microemulsions and liquid crystal phases, which can be exploited as drug delivery systems because their nanostructured organization can control drug release. Therefore, the purpose of this study was to assess the potential of systems containing polyoxypropylene (5) polyoxyethylene (20) cetyl ether as surfactant, oleic acid or mineral oil as the oily phase, and water to be used as a platform in the development of topical drug delivery systems. Physicochemical characterization of the systems was performed by polarized light microscopy (PLM), small-angle X-ray scattering (SAXS), rheological tests and texture profile analysis. The ternary phase diagrams showed that combinations of surfactant/mineral oil/water and surfactant/oleic acid/water could form various thermodynamically stable structures, such as microemulsions and liquid crystals. The oily phases, oleic acid and mineral oil, changed the rheological, mechanical and adhesive properties of systems containing polyoxypropylene (5) polyoxyethylene (20) cetyl ether.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq