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89 result(s) for "Colombo, Miriam"
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Tumour homing and therapeutic effect of colloidal nanoparticles depend on the number of attached antibodies
Active targeting of nanoparticles to tumours can be achieved by conjugation with specific antibodies. Specific active targeting of the HER2 receptor is demonstrated in vitro and in vivo with a subcutaneous MCF-7 breast cancer mouse model with trastuzumab-functionalized gold nanoparticles. The number of attached antibodies per nanoparticle was precisely controlled in a way that each nanoparticle was conjugated with either exactly one or exactly two antibodies. As expected, in vitro we found a moderate increase in targeting efficiency of nanoparticles with two instead of just one antibody attached per nanoparticle. However, the in vivo data demonstrate that best effect is obtained for nanoparticles with only exactly one antibody. There is indication that this is based on a size-related effect. These results highlight the importance of precisely controlling the ligand density on the nanoparticle surface for optimizing active targeting, and that less antibodies can exhibit more effect. A common strategy to target nanoparticles to tumours is conjugation with specific antibodies, targeting protein expressed preferentially by cancer cells. Here the authors show that the number of antibodies bound to the nanoparticle influences the targeting ability in vitro and in vivo .
Negatively charged silver nanoparticles with potent antibacterial activity and reduced toxicity for pharmaceutical preparations
The discovery of new solutions with antibacterial activity as efficient and safe alternatives to common preservatives (such as parabens) and to combat emerging infections and drug-resistant bacterial pathogens is highly expected in cosmetics and pharmaceutics. Colloidal silver nanoparticles (NPs) are attracting interest as novel effective antimicrobial agents for the prevention of several infectious diseases. Water-soluble, negatively charged silver nanoparticles (AgNPs) were synthesized by reduction with citric and tannic acid and characterized by transmission electron microscopy, dynamic light scattering, zeta potential, differential centrifuge sedimentation, and ultraviolet-visible spectroscopy. AgNPs were tested with model Gram-negative and Gram-positive bacteria in comparison to two different kinds of commercially available AgNPs. In this work, AgNPs with higher antibacterial activity compared to the commercially available colloidal silver solutions were prepared and investigated. Bacteria were plated and the antibacterial activity was tested at the same concentration of silver ions in all samples. The AgNPs did not show any significant reduction in the antibacterial activity for an acceptable time period. In addition, AgNPs were transferred to organic phase and retained their antibacterial efficacy in both aqueous and nonaqueous media and exhibited no toxicity in eukaryotic cells. We developed AgNPs with a 20 nm diameter and negative zeta potential with powerful antibacterial activity and low toxicity compared to currently available colloidal silver, suitable for cosmetic preservatives and pharmaceutical preparations administrable to humans and/or animals as needed.
Malnutrition and related risk factors in older adults from different health-care settings: an enable study
The origin of malnutrition in older age is multifactorial and risk factors may vary according to health and living situation. The present study aimed to identify setting-specific risk profiles of malnutrition in older adults and to investigate the association of the number of individual risk factors with malnutrition. Data of four cross-sectional studies were harmonized and uniformly analysed. Malnutrition was defined as BMI < 20 kg/m2 and/or weight loss of >3 kg in the previous 3-6 months. Associations between factors of six domains (demographics, health, mental function, physical function, dietary intake-related problems, dietary behaviour), the number of individual risk factors and malnutrition were analysed using logistic regression. Community (CD), geriatric day hospital (GDH), home care (HC), nursing home (NH). CD older adults (n 1073), GDH patients (n 180), HC receivers (n 335) and NH residents (n 197), all ≥65 years. Malnutrition prevalence was lower in CD (11 %) than in the other settings (16-19 %). In the CD sample, poor appetite, difficulties with eating, respiratory and gastrointestinal diseases were associated with malnutrition; in GDH patients, poor appetite and respiratory diseases; in HC receivers, younger age, poor appetite and nausea; and in NH residents, older age and mobility limitations. In all settings the likelihood of malnutrition increased with the number of potential individual risk factors. The study indicates a varying relevance of certain risk factors of malnutrition in different settings. However, the relationship of the number of individual risk factors with malnutrition in all settings implies comprehensive approaches to identify persons at risk of malnutrition early.
Exploring Bovine Serum Albumin (BSA) as a Facile Substrate for Testing of Osmolytes as Cosmetic Ingredients
Osmolytes, cellular compounds that maintain osmotic balance and integrity, are gaining attention in cosmetics for their ability to modulate protein folding and stability. Their incorporation into hair and skin care products enhances hydration and strengthens cellular structures. As the cosmetic industry seeks innovative and effective ingredients, osmolytes remain promising candidates for further advancing technologies. This study evaluates the protective effects of four osmolytes—betaine, erythritol, glycine, and isopentyldiol—on bovine serum albumin (BSA), as a substrate, under stressors such as UV irradiation, extreme temperatures, pH changes, surfactants, and oxidative stress. Protein stability was assessed via fluorescence emission. Only betaine at 0.50% w/w provided significant protection under oxidative stress, while glycine was the most effective osmolyte under basic and acidic pH and UVC radiation. Betaine showed potential in mitigating cold-induced stress but increased stress under UVA radiation, highlighting its condition-specific effects. The study emphasizes the need for comprehensive screening and synergistic testing of osmolytes to optimize cosmetic formulations for diverse stressors. Among the tested osmolytes, glycine is a promising candidate for skin and hair care products, though further research is needed. These findings provide a rapid, cost-effective method to evaluate osmolytes’ potential, offering valuable insights for cosmetic formulation.
Investigation of antitumor activities of trastuzumab delivered by PLGA nanoparticles
We report the development of an efficient antibody delivery system for the incorporation of trastuzumab (TZ) into poly(lactic- -glycolic) acid nanoparticles (PLGA NPs). The aim of the work was to overcome the current limitations in the clinical use of therapeutic antibodies, including immunogenicity, poor pharmacokinetics, low tumor penetration and safety issues. Trastuzumab-loaded PLGA NPs (PLGA-TZ) were synthesized according to a double emulsion method. The same protocol was used to produce control batches of nonspecific IgG-loaded NPs and empty PLGA NPs. After release of TZ from PLGA NPs, the effects on the main biological activities of the antibody were evaluated on SKBR3 (human epidermal growth factor receptor 2 [HER2]-positive breast cancer cell line), including specific binding to HER2, phosphorylation of HER2 (Y1248), degradation of HER2 protein and antibody-dependent cell-mediated cytotoxicity (ADCC) mechanism. In addition, an MTT assay was performed for treating SKBR3 cells with PLGA NPs loaded with TZ and doxorubicin to evaluate the cytotoxic activity of the combined treatment. TZ was gradually released in a prolonged way over 30 days. The physical characterization performed with circular dichroism, Fourier transform infrared and fluorescence spectroscopy of TZ after release demonstrated that no structural alterations occurred compared to the native antibody. In vitro experiments using SKBR3 cells showed that TZ released from PLGA NPs maintained the same biological activity of native TZ. PLGA NPs allowed a good co-encapsulation efficiency of TZ and doxorubicin resulting in improved therapy. With the TZ case study, we demonstrate that the distinctive features of therapeutic monoclonal antibodies, including molecular targeting efficiency, capability to inhibit or properly affect the regulatory signaling pathways of cancer cells and stimulation of the ADCC, are fully preserved after loading into and release from PLGA NPs. In addition, PLGA NPs are shown to allow for the simultaneous incorporation of TZ and conventional chemotherapeutics, resulting in a potent antitumor nanodrug well suited for in situ combination and neoadjuvant therapy.
Natural Products from Mangroves: An Overview of the Anticancer Potential of Avicennia marina
Exploring the potential of natural extracts for pharmaceutical applications in the treatment of different diseases is an emerging field of medical research, owing to the tremendous advantages that they can offer. These include compound sustainability due to the natural origin and virtually unlimited availability. In addition, they contribute to promoting the countries in which they are extracted and manufactured. For this reason, wild active compounds derived from plants are attracting increasing interest due to their beneficial properties. Among them, Avicennia marina has been recently recognized as a potential source of natural substances with therapeutic activities for anti-cancer treatment. A. marina beneficially supplies different chemical compounds, including cyclic triterpenoids, flavonoids, iridoids, naphtaquinones, polyphenols, polysaccharides, and steroids, most of them exhibiting potent antitumor activity. The in vivo and in vitro studies on different models of solid tumors demonstrated its dose-dependent activity. Moreover, the possibility to formulate the A. marina extracted molecules in nanoparticles allowed researchers to ameliorate the therapeutic outcome of treatments exploiting improved selectivity toward cancer cells, thus reducing the side effects due to nonspecific spread.
Heparin–Superparamagnetic Iron Oxide Nanoparticles for Theranostic Applications
In this study, superparamagnetic iron oxide nanoparticles (SPIONs) were engineered with an organic coating composed of low molecular weight heparin (LMWH) and bovine serum albumin (BSA), providing heparin-based nanoparticle systems (LMWH@SPIONs). The purpose was to merge the properties of the heparin skeleton and an inorganic core to build up a targeted theranostic nanosystem, which was eventually enhanced by loading a chemotherapeutic agent. Iron oxide cores were prepared via the co-precipitation of iron salts in an alkaline environment and oleic acid (OA) capping. Dopamine (DA) was covalently linked to BSA and LMWH by amide linkages via carbodiimide coupling. The following ligand exchange reaction between the DA-BSA/DA-LMWH and OA was conducted in a biphasic system composed of water and hexane, affording LMWH@SPIONs stabilized in water by polystyrene sulfonate (PSS). Their size and morphology were investigated via dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. The LMWH@SPIONs’ cytotoxicity was tested, showing marginal or no toxicity for samples prepared with PSS at concentrations of 50 µg/mL. Their inhibitory activity on the heparanase enzyme was measured, showing an effective inhibition at concentrations comparable to G4000 (N-desulfo-N-acetyl heparin, a non-anticoagulant and antiheparanase heparin derivative; Roneparstat). The LMWH@SPION encapsulation of paclitaxel (PTX) enhanced the antitumor effect of this chemotherapeutic on breast cancer cells, likely due to an improved internalization of the nanoformulated drug with respect to the free molecule. Lastly, time-domain NMR (TD-NMR) experiments were conducted on LMWH@SPIONs obtaining relaxivity values within the same order of magnitude as currently used commercial contrast agents.
Implementing interprofessional video consultations with general practitioners and psychiatrists in correctional facilities in Germany: results from a mixed-methods study
Background Adequate health care in correctional facilities is often limited by staff shortage, which entails time-consuming consultations with physicians outside of these facilities. Video consultations (VC) have been implemented in many different health care settings and may also be useful in correctional facilities. As part of a pilot project, synchronous VC were implemented in five correctional facilities in Germany in June 2018. The aim of this study was to describe the implementation process from the providers’ perspective and to identify factors promoting or inhibiting the implementation process of VC with a focus on interprofessional collaboration between nursing staff and telemedicine physicians. Methods As part of the mixed-methods evaluation of the pilot project, site visits to the five correctional facilities were carried out. Nursing staff from the five correctional facilities ( n= 49) and telemedicine physicians ( n= 10) were asked to participate in interviews and a questionnaire survey. Interviews were analyzed using qualitative content analysis and questionnaires were evaluated using descriptive statistical methods. The results from both data sources were integrated and discussed in the framework of Normalization Process Theory. Results Interviews were conducted with 24.5% ( n= 12) of nursing staff and 20.0% ( n= 2) of telemedicine physicians, while questionnaires were returned by 22.5% ( n= 11) of nursing staff and 33.3% ( n= 3) of telemedicine physicians. VC with general practitioners and psychiatrists were perceived as an additional support during times when physicians were absent from the correctional facilities. Allocating telemedicine physicians to specific correctional facilities might further improve interprofessional collaboration with nursing staff during VC. Inhibiting factors comprised the lack of integrating nursing staff into the implementation process, increased workload, insufficient training and the implementation of VC at an inconvenient time. Conclusions To summarize, VC are a promising supplement to face-to-face health care in correctional facilities despite several limitations. These might be compensated by improving interprofessional cooperation and by integrating telemedicine physicians into local health care teams.
Anti-MAdCAM-1-Conjugated Nanocarriers Delivering Quantum Dots Enable Specific Imaging of Inflammatory Bowel Disease
Assessment of inflammatory bowel disease (IBD) currently relies on aspecific clinical signs of bowel inflammation. Specific imaging of the diseased bowel regions is still lacking. Here, we investigate mucosal addressin cell adhesion molecule 1 (MAdCAM-1) as a reliable and specific endothelial target for engineered nanoparticles delivering imaging agents to obtain an exact mapping of diseased bowel foci. We generated a nanodevice composed of PLGA-PEG coupled with anti-MAdCAM-1 antibody half-chains and loaded with quantum dots (P@QD-MdC NPs). Bowel localization and systemic biodistribution of the nanoconjugate were analyzed upon injection in a murine model of chronic IBD obtained through repeated administration of dextran sulfate sodium salt. Specificity for diseased bowel regions was also assessed ex vivo in human specimens from patients with IBD. Potential for development as contrast agent in magnetic resonance imaging was assessed by preliminary study on animal model. Synthesized nanoparticles revealed good stability and monodispersity. Molecular targeting properties were analyzed in vitro in a cell culture model. Upon intravenous injection, P@QD-MdC NPs were localized in the bowel of colitic mice, with enhanced accumulation at 24 h post-injection compared to untargeted nanoparticles (p<0.05). Nanoparticles injection did not induce histologic lesions in non-target organs. Ex vivo exposure of human bowel specimens to P@QD-MdC NPs revealed specific recognition of the diseased regions vs uninvolved tracts (p<0.0001). After loading with appropriate contrast agent, the nanoparticles enabled localized contrast enhancement of bowel mucosa in the rectum of treated mice. P@QD-MdC NPs efficiently detected bowel inflammation foci, accurately following the expression pattern of MAdCAM-1. Fine-tuning of this nanoconjugate with appropriate imaging agents offers a promising non-invasive tool for specific IBD diagnosis.
Phytochemical Profiling, Antioxidant Activity, and In Vitro Cytotoxic Potential of Mangrove Avicennia marina
Background: Avicennia marina (Forsk.) Vierh., a widely distributed mangrove species, is known for its diverse secondary metabolites with potential pharmacological applications. Despite its dominance in the Arabian Gulf, where A. marina may have adapted to extreme environmental conditions with a distinct set of bioactive molecules, research in this region remains limited. Methods: This study investigates the phytochemical composition, antioxidant activity, and in vitro cytotoxicity of extracts from different plant parts, including roots, leaves, propagules, pericarps, and cotyledons, collected in the United Arab Emirates (UAE). Extracts were analyzed using ultra-pressure liquid chromatography coupled with high-resolution mass spectrometry (UPLC-HRMS). Antioxidant activity was assessed using DPPH and ABTS assays, while cytotoxicity was evaluated against human cancer and normal cell lines. Results: Analysis revealed 49 compounds, including iridoid glycosides, hydroxycinnamic acids, phenylethanoid glycosides, flavonoid glycosides, and triterpene saponins, several reported for the first time in A. marina and mangroves. The pericarp and root extracts exhibited the highest scavenging activity (DPPH: 187.14 ± 2.87 and 128.25 ± 1.12; ABTS: 217.16 ± 2.67 and 147.21 ± 2.42 μmol TE/g, respectively), correlating with phenylethanoid content. The root extract also displayed the highest cytotoxicity, with IC50 values of 58.46, 81.98, and 108.10 μg/mL against MDA-MB-231, SW480, and E705, respectively. In silico analysis identified triterpene saponins as potential contributors. Conclusions: These findings highlight the root extract of A. marina as a promising source of bioactive compounds with potential antioxidant and anticancer applications, supporting further exploration for novel therapeutic candidates.