6 research outputs found

    Computational and experimental model of transdermal iontophorethic drug delivery system

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    The concept of iontophoresis is often applied to increase the transdermal transport of drugs and other bioactive agents into the skin or other tissues. It is a non-invasive drug delivery method which involves electromigration and electroosmosis in addition to diffusion and is shown to be a viable alternative to conventional administration routs such as oral, hypodermic and intravenous injection. In this study we investigated, experimentally and numerically, in vitro drug delivery of dexamethasone sodium phosphate to porcine skin. Different current densities, delivery durations and drug loads were investigated experimentally and introduced as boundary conditions for numerical simulations. Nernst-Planck equation was used for calculation of active substance flux through equivalent model of homogeneous hydrogel and skin layers. The obtained numerical results were in good agreement with experimental observations. A comprehensive in-silico platform, which includes appropriate numerical tools for fitting, could contribute to iontophoretic drug-delivery devices design and correct dosage and drug clearance profiles as well as to perform much faster in-silico experiments to better determine parameters and performance criteria of iontophoretic drug delivery

    PVA Cryogel as model hydrogel for iontophoretic transdermal drug delivery investigations. Comparison with PAA/PVA and PAA/PVP interpenetrating networks

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    The use of polyvinyl alcohol (PVA) cryogel as a model hydrogel for iontophoretic transdermal investigations is proposed. Due to the excellent combination of its properties, it could be used for evaluating iontophoretic transdermal delivery of variety of drugs, regardless of pK(a), pH or presence of auxiliary ions. Applicability of PVA Cryogel for drug delivery purposes was compared to those of polyacrylic acid/polyvinyl alcohol (PAA/PVA) and polyacrylic acid/polyvinylpyrrolidone (PAA/PVP) adhesive interpenetrating networks. Swelling properties of PVA Cryogel were shown to be almost independent on pH and NaCl concentration, while swelling of PAA-based gels was significantly affected. Addition of PVA and PVP to PAA decreased swelling degrees and increased adhesivity and compression moduli. Iontophoretic experiments were performed using a donor gel/skin/receptor gel configuration; current density and delivery duration were varied. Dexamethasone sodium phosphate was used as model drug molecule. PVA Cryogel was used for investigating the influence of NaCl concentration, which can alter the amount of current carried by the drug ions and, therefore, the delivery rate. By using PVA Cryogel it was possible to easily determine the amount of drug permeated through the skin into the receptor gel, the amount retained by the skin and the amount remained in the donor hydrogel. Decreasing NaCl concentration in PVA Cryogel resulted in higher total amounts of drug delivered and significantly enhanced drug permeation through the lower layers of the skin into the receptor hydrogel

    MRI versus non-MRI diagnostic pathways before radical prostatectomy: Impact on nerve-sparing, positive surgical margins, and biochemical recurrence.

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    PURPOSE: Magnetic resonance imaging (MRI) prior to biopsy has improved detection of clinically significant prostate cancer (CaP), but its impact on surgical outcomes is less well established. We compared MRI vs. non-MRI diagnostic pathways among patients receiving radical prostatectomy (RP) for impact on surgical outcomes. MATERIALS AND METHODS: Men diagnosed with CaP and receiving RP at Loyola University Medical Center (2014-2021) were categorized into MRI or non-MRI diagnostic pathways based on receipt of MRI before prostate biopsy. Primary outcomes of interest included positive surgical margin (PSM) rates, the performance of bilateral nerve-sparing, and biochemical recurrence (BCR). Multivariable logistic regression models, Kaplan-Meier curves, and Cox proportional hazards regression were employed. RESULTS: Of 609 patients, 281 (46.1%) were in the MRI and 328 (53.9%) in the non-MRI groups. MRI patients had similar PSA, biopsy grade group (GG) distribution, RP GG, pT stage, and RP CaP volume compared to non-MRI patients. PSM rates were not statistically different for the MRI vs. non-MRI groups (22.8% vs. 26.8%, P = 0.25). Bilateral nerve-sparing rates were higher for the MRI vs. non-MRI groups (OR 1.95 (95%CI 1.32-2.88), P = 0.001). The MRI group demonstrated improved BCR (HR 0.64 (95%CI 0.41-0.99), P = 0.04) after adjustment for age, PSA, RP GG, pT, pN, and PSM status. On meta-analysis, a 5.2% PSM reduction was observed but high heterogeneity for use of nerve-sparing. CONCLUSIONS: An MRI-based diagnostic approach selected patients for RP with a small reduction in PSM rates, greater utilization of bilateral nerve-sparing, and improved cancer control by BCR compared to a non-MRI approach even after adjustment for known prognostic factors

    MRI vs Transrectal Ultrasound to Estimate Prostate Volume and PSAD: Impact on Prostate Cancer Detection.

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    OBJECTIVES: To compare multiparametric magnetic resonance imaging (mpMRI) and transrectal ultrasound (TRUS) to estimate prostate volume and prostate specific antigen density (PSAD) as well as subsequent impact on prostate cancer (PCa) detection. METHODS: Patients referred for mpMRI prior to mpMRI-TRUS fusion-guided prostate biopsy between 2015 and 2020 were identified. Volume and calculated PSAD by mpMRI and TRUS were compared. Associations with presence of any PCa and clinically significant PCa (csPCa; Gleason ≥3 + 4) were evaluated using linear regression (interaction by volume quartile), logistic regression, and receiver operating characteristics. RESULTS: Among 640 men, TRUS underestimated prostate volume relative to mpMRI (median 49.2cc vs. 54.1cc) with 8% lower volume per cc up to 77.5cc (First-third quartile) and 39% lower volume per additional cc above 77.5cc (fourth quartile). For men undergoing radical prostatectomy, mpMRI had a higher correlation coefficient relative to TRUS (0.913 vs 0.878) when compared to surgical pathology. mpMRI PSAD had slightly higher odds vs TRUS PSAD for detecting any PCa (OR 2.94 and OR 2.78, both P CONCLUSION: TRUS underestimates prostate volume relative to mpMRI. PSAD based on mpMRI may be better associated with detection of PCa compared to TRUS, but utility of PSAD may be limited for larger prostates

    The Incidence and Genetic Diversity of Potato virus S in Serbian Seed Potato Crops

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    It is essential that certified potatoes are free from known viruses which can negatively affect quality and yield. However, very little is known about the distribution and frequency of Potato virus S (PVS) in Serbia. Until 2014, PVS was present sporadically in the domestic seed potato production. The incidence of PVS was studied by a molecular method over 3 years (2014-2016) in four important potato-growing regions (Moravidd. Zlatiborski, Raski and Macvanski) and in different cultivars. The results showed that the incidence of PVS increased steadily over 3 years from 1.52 to 8.84%. The Moravicki region had the highest incidence (13.06%) and Desiree was the most susceptible cultivar with a mean PVS incidence of 8.2% followed by Marabel and Riviera. The highest significant statistical difference was between the cultivars and in the interaction between cultivars and regions. A detailed phylogenic analysis of the tested isolates contained that Serbian PVS belongs to PVSO. Of the 18 Serbian PVS isolates included in this study, eight were grouped into the PVSO cluster and formed a subgroup (O-I) with isolates from the USA, Syria, Korea and Chile. Ten Serbian isolates of PVS together with the isolates from Iran were clustered in a branch of subgroup O-VII. This study constitutes the fast report of PVS isolates in Serbia which are capable of infecting Chenopodium quinoa and inducing the symptoms of local chlorotic lesions
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