65 research outputs found
Propagating Lyapunov Functions to Prove Noise--induced Stabilization
We investigate an example of noise-induced stabilization in the plane that
was also considered in (Gawedzki, Herzog, Wehr 2010) and (Birrell, Herzog, Wehr
2011). We show that despite the deterministic system not being globally stable,
the addition of additive noise in the vertical direction leads to a unique
invariant probability measure to which the system converges at a uniform,
exponential rate. These facts are established primarily through the
construction of a Lyapunov function which we generate as the solution to a
sequence of Poisson equations. Unlike a number of other works, however, our
Lyapunov function is constructed in a systematic way, and we present a
meta-algorithm we hope will be applicable to other problems. We conclude by
proving positivity properties of the transition density by using Malliavin
calculus via some unusually explicit calculations.Comment: 41 pages, 3 figures Added picture to this version and simplified the
control theory discussion significantl
In situ conjugation of dithiophenol maleimide polymers and oxytocin for stable and reversible polymer–peptide conjugates
The in situ one-pot synthesis of peptide–polymer bioconjugates is reported. Conjugation occurs efficiently without the need for purification of dithiophenol maleimide functionalized polymer as a disulfide bridging agent for the therapeutic oxytocin. Conjugation of polymers was demonstrated to be reversible and to significantly improve the solution stability of oxytocin
EGF functionalized polymer-coated gold nanoparticles promote EGF photostability and EGFR internalization for photothermal therapy
The application of functionalized nanocarriers on photothermal therapy for cancer ablation has wide interest. The success of this application depends on the therapeutic efficiency and biocompatibility of the system, but also on the stability and biorecognition of the conjugated protein. This study aims at investigating the hypothesis that EGF functionalized polymer -coated gold nanoparticles promote EGF photostability and EGFR internalization, making these conjugated particles suitable for photothermal therapy. The conjugated gold nanoparticles (100-200 nm) showed a plasmon absorption band located within the near infrared range (650-900 nm), optimal for photothermal therapy applications. The effects of temperature, of polymer-coated gold nanoparticles and of UVB light (295nm) on the fluorescence properties of EGF have been investigated with steady-state and time-resolved fluorescence spectroscopy. The fluorescence properties of EGF, including the formation of Trp and Tyr photoproducts, is modulated by temperature and by the intensity of the excitation light. The presence of polymeric-coated gold nanoparticles reduced or even avoided the formation of Trp and Tyr photoproducts when EGF is exposed to UVB light, protecting this way the structure and function of EGF. Cytotoxicity studies of conjugated nanoparticles carried out in normal-like human keratinocytes showed small, concentration dependent decreases in cell viability (0-25%). Moreover, conjugated nanoparticles could activate and induce the internalization of overexpressed Epidermal Growth Factor Receptor in human lung carcinoma cells. In conclusion, the gold nanoparticles conjugated with Epidermal Growth Factor and coated with biopolymers developed in this work, show a potential application for near infrared photothermal therapy, which may efficiently destroy solid tumours, reducing the damage of the healthy tissue.Support was provided by: Fundacao para a Ciencia e Tecnologia (FCT) for the financial support under the project reference PTDC/BBB-BMC/0611/2012 [https://www.fct.pt/apoios/projectos)]. The work at CBMA was supported by the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) funded by national funds through the FCT I.P. and by the ERDF through the COMPETE2020 - Programa Operacional Competitividade e Internacionalizacao (POCI) [https://www.fct.pt/apoios/projectos]; European Commission through the project H2020-644242-SAPHELY (https://saphely.eu/project.php) and the project H2020-634013-2-PHOCNOSIS [http://cordis.europa.eu/project/rcn/193268_en.html].The authors would like to thank Fundacao para a Ciencia e Tecnologia (FCT) for the financial support under the project reference PTDC/BBB-BMC/0611/2012. The work at CBMA was supported by the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) funded by national funds through the FCT I.P. and by the ERDF through the COMPETE2020 - Programa Operacional Competitividade e Internacionalizacao (POCI). The authors acknowledge the funding from the European Commission through the project H2020-644242-SAPHELY and the project H2020-634013-2-PHOCNOSIS. Finally, the authors would also like to thank the master student Joao Lopes from Universidade Lusofona (Portugal) for the help with in vitro cytotoxic assays. Isabel Correia acknowledges FCT for Investigator FCT contract.info:eu-repo/semantics/publishedVersio
Vitamin D3 supplementation reduced Staphylococcus aureus co- lonization in the skin of pediatric patients with atopic dermatitis.
Abstract
Atopic dermatitis (AD) is a common skin disorder resulting in malfunctioning of the skin barrier and immune system that facilitate the growth of various microorganisms. Several studies reported that there was a significant reduction of vitamin D and cathelicidin levels in AD patients. It was also reported that the administration of vitamin D in AD patients sharply increased cathelicidin level that can be advantageous as a skin defense against microbial infection. In this study the supplementation of vitamin D3 was administered to AD pediatric patients and the ability of Vitamin D3 to reduce infections in AD patients was measured by observing Staphylococcus aureus colonization. A double-blind randomized experimental study was carried out after appropriate sampling on 20 AD patients who came for treatment in Dermatopediatric Division of Dr. Soetomo General Hospital Surabaya and met the criteria for inclusion. A supplementation of vitamin D3 syrup was used in the experimental group, and a placebo syrup was used in the control group. Lesional skin swabs were taken before and after 28 days supplementation of vitamin D3. There was significant reduction of the Staphylococcus aureus colonization after vitamin D3 administration while there was no significant difference in the number of Staphylococcus aureus colonies after placebo administration. The statistic analysis of the two groups confirmed that there was a significant difference in the percentage of Staphylococcus aureus colonization in the vitamin D3 group compared to placebo. The supplementation of vitamin D3 decreased Staphylococcus aureus colonization in AD children, without significant side effects
Effectiveness of Botulinum Toxin on Pain in Stroke Patients Suffering from Upper Limb Spastic Dystonia
open11noThis observational study aimed at investigating pain in stroke patients with upper limb spastic dystonia. Forty-one consecutive patients were enrolled. A 0–10 numeric rating scale was used to evaluate pain at rest and during muscle tone assessment. Patients were asked to indicate the most painful joint at passive mobilization (shoulder, elbow, wrist-fingers). The DN4 questionnaire was administered to disclose neuropathic pain. All patients were assessed just before and 1 month after incobotulinumtoxin-A treatment. Pain was present in 22 patients, worsened or triggered by passive muscle stretching. DN4 scored < 4 in 20 patients. The most painful joints were wrist–fingers in 12 patients, elbow in 5 patients and shoulder in the remaining 5 patients. Both elbow and wrist– fingers pain correlated with muscle tone. BoNT-A treatment reduced pain in all the joints, including the shoulder. We discussed that nociceptive pain is present in a vast proportion of patients with upper limb spastic dystonia. BoNT-A treatment reduced both spastic dystonia and pain in all the joints but the shoulder, where the effect on pain could be mediated by the reduction of pathological postures involving the other joints.openTrompetto C.; Marinelli L.; Mori L.; Puce L.; Avanti C.; Saretti E.; Biasotti G.; Amella R.; Cotellessa F.; Restivo D.A.; Curra A.Trompetto, C.; Marinelli, L.; Mori, L.; Puce, L.; Avanti, C.; Saretti, E.; Biasotti, G.; Amella, R.; Cotellessa, F.; Restivo, D. A.; Curra, A
A study of the effect of terlipressin with albumin vs only albumin in patients diagnosed with hepatorenal syndrome (HRS)
Background: Hepatorenal syndrome (HRS) is a potentially reversible, functional renal failure that occurs in patients with advanced liver disease. HRS is generally characterized by increased serum creatinine, azotemia, reduced diuresis, increased urine osmolarity, and reduced urine sodium values without signs of organic kidney damage1. AIM: The aim of the study is to investigate the efficacy, adverse effects, and outcomes of Terlipressin with Albumin vs. only Albumin in patients diagnosed with hepatorenal syndrome. Material and methods: A single centred hospital-based descriptive ,observational study was conducted in patients admitted with a diagnosis of hepatorenal syndrome for 18 months (October 2019 to March 2021). A total 80 cases were studied. Results: All the parameters including Total Bilirubin, SGPT ( Serum glutamate pyruvate transaminase ), INR ( Internationalised normalised ratio ) and Serum Albumin were found to be similar ion both the groups except except SGOT (p=0.002) which was found to be significantly lower in Terlipressin +Albumin treatment group (61.89±47.83) compared to only albumin .(96.80±109.30). Those who were treated with Terlipressin +Albumin showed significant decrease in serum creatinine. A significant decrease in serum creatinine was observed at Day 5 (1.73±1.49) from Day 1 (3.47±1.68) making a mean percentage decrease of 50.14%
Karakterisasi Dan Stabilitas Fisik Mikroemulsi Tipe A/M Dengan Fase Minyak LCT Dan MCT
Pada penelitian ini dilakukan formulasi, karakterisasi dan stabilitas fisik sediaan mikroemulsi tipe air dalam minyak. Minyak yang digunakan sebagai fase minyak dalam pembuatan mikroemulsi adalah VCO (F1), minyak kelapa sawit (F2), minyak zaitun (F3) dan minyak kedelai (F4), fase air aquademineralisata, Span® 80 dan Tween® 80 sebagai surfaktan dan propanol sebagai kosurfaktan. Setiap formula dilakukan 3 replikasi dan ditentukan karakteristik fisik yang meliputi pengamatan organoleptis, pengukuran berat jenis, pengukuran droplet, pengukuran viskositas dan sifat alir, dan pengukuran pH. Penentuan karakteristik fisik dilakukan pada saat awal terbentuk mikroemulsi dan setelah penyimpanan selama 5 minggu dalam suhu ruang 27,5ºC. Selain itu, juga dilakukan uji stabilitas fisik yang meliputi uji sentrifugasi dengan kecepatan 10.000 rpm selama 30 menit, uji freeze-thaw selama 6 siklus, dan uji heating stability dengan oven suhu 60ºC, 70ºC, 80ºC, 90ºC, dan 100ºC selama 5 jam. Dari data yang didapatkan dilakukan analisis statistic menggunakan metode t-Test dan one way ANOVA. Dari penentuan karakteristik dan stabilitas fisik yang telah dilakukan didapatkan hasil bahwa mikroemulsi dengan minyak VCO, minyak kelapa sawit dan minyak kedelai memiliki karakteristik dan stabilitas fisik yang lebih baik dibandingkan dengan mikroemulsi dengan minyak zaitu
Photoprotective potential of lycopene, beta-carotene, vitamin E, vitamin C and carnosic acid in UVA-irradiated human skin fibroblasts
The photoprotective potential of the dietary antioxidants vitamin C, vitamin E, lycopene, beta-carotene, and the rosemary polyphenol, carnosic acid, was tested in human dermal fibroblasts exposed to ultraviolet-A (UVA) light. The carotenoids were prepared in special nanoparticle formulations together with vitamin C and/or vitamin E. Nanoparticle formulations, in contrast to dimethylsulphoxide, stablized lycopene in the cell culture medium and allowed efficient cellular uptake. The presence of vitamin E in the formulation further increased the stability and cellular uptake of lycopene. UVA irradiation of the human skin fibroblasts led to a 10-15-fold rise in metalloproteinase 1 (MMP-1) mRNA. This rise was suppressed in the presence of low microM concentrations of vitamin E, vitamin C, or carnosic acid but not with beta-carotene or lycopene. Indeed, in the presence of 0.5-1.0 microM beta-carotene or lycopene, the UVA-induced MMP-1 mRNA was further increased by 1.5-2-fold. This increase was totally suppressed when vitamin E was included in the nanoparticle formulation. Heme-oxygenase 1 (HO-1) mRNA expression was strongly induced by UVA irradiation but none of the antioxidants inhibited this effect at the concentrations used in this study. Indeed, beta-carotene or lycopene (0.5-1.0 microM) led to a further 1.5-fold rise in the UVA-induced HO-1 mRNA levels. In conclusion, vitamin C, vitamin E, and carnosic acid showed photoprotective potential. Lycopene and beta-carotene did not protect on their own but in the presence of vitamin E, their stability in culture was improved and the rise in MMP-1 mRNA expression was suppressed, suggesting a requirement for antioxidant protection of the carotenoids against formation of oxidative derivatives that can influence the cellular and molecular response
Liver X receptor preferentially activates de novo lipogenesis in human preadipocytes
The liver X receptor (LXR) was demonstrated to play a key role in cholesterol metabolism in liver, intestine and macrophage. However, its function on the regulation of preadipocyte differentiation remains unclear since contradictory results were reported. The objective of the present study was to unravel the functionality of LXR in human preadipocytes. We show that the LXR agonist T0901317 strongly stimulated the expression of SREBP-1c and the lipogenic enzymes ACC-1, FAS and SCD-1 in both the human preadipose cell line Chub-S7 as well as human primary stromal vascular fraction (SVF) cells. The effects on gene expression were associated with the stimulation of de novo lipogenesis in both cell models, resulting in the induction of lipid accumulation. In contrast with a PPARgamma agonist (BRL49653), T0901317 enhanced only slightly the expression of PPARgamma dependent genes (PPARgamma, aP2 and adiponectin) in Chub-S7 cells and failed to change their expression in human SVF cells. These results show that LXR stimulated preferentially triglyceride accumulation in human preadipocytes via the induction of de novo lipogenesis, rather than activating the differentiation process through PPARgamma activation
The Formation of Oxytocin Dimers is Suppressed by the Zinc–Aspartate–Oxytocin Complex
The aim of this study was to investigate the effect of divalent metal ions (Ca, Mg2+, and Zn2+) on the stability of oxytocin in aspartate buffer (pH 4.5) and to determine their interaction with the peptide in aqueous solution. Reversed-phase high-performance liquid chromatography and high-performance size-exclusion chromatography measurements indicated that after 4 weeks of storage at 55°C, all tested divalent metal ions improved the stability of oxytocin in aspartate-buffered solutions (pH 4.5). However, the stabilizing effects of Zn2+ were by far superior compared with Ca2+ and Mg2+. Liquid chromatography–tandem mass spectrometry showed that the combination of aspartate and Zn2+ in particular suppressed the formation of peptide dimers. As shown by isothermal titration calorimetry, Zn2+ interacted with oxytocin in the presence of aspartate buffer, whereas Ca2+ or Mg2+ did not. In conclusion, the stability of oxytocin in the aspartate-buffered solution is strongly improved in the presence of Zn2+, and the stabilization effect is correlated with the ability of the divalent metal ions in aspartate buffer to interact with oxytocin. The reported results are discussed in relation to the possible mode of interactions among the peptide, Zn2+, and buffer components leading to the observed stabilization effects.
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