Search results for "Urea"
showing 10 items of 888 documents
Enhanced thermodynamic and kinetic stability of calix[4]arene dimers locked in the cone conformation.
2004
Wide rim tetraurea derivatives (2a,b) have been prepared from a calix[4]arene rigidified in the cone conformation by two diethyleneglycol ether bridges between adjacent oxygens. In comparison to the analogous tetraurea derivatives (3a,b) of a tetrapentoxy calix[4]arene, 2a,b show an increased thermodynamic stability in mixtures of CDCl(3) and DMSO-d(6). Their kinetic stability as expressed by the rate of guest exchange (benzene or cyclohexane against the solvent benzene-d(6)) is also strongly increased by factors of 30-38. Noticeable differences for the inclusion of selected guests are found.
Guest exchange in dimeric capsules of a tetraurea calix[4]arene in the solid state
2007
A solid powder of hydrogen bonded dimers of a tetraurea calix[4]arene is able to exchange the encapsulated guest in contact with the vapor of a second guest. The molecules of a guest-free powder obtained from a polar solvent cannot rearrange in the solid phase to form new guest-filled capsules under these conditions.
Acid rearrangment of epoxy-germacranolides and absolute configuration of 1beta, 10alpha-epoxy-salonitenolide
2010
The acid-catalyzed cyclization of mono epoxides of cnicin acetonide (3) was investigated. Several 6,12-eudesmanolides were obtained, and their stereochemistry established by extensive spectroscopic analyses. Chemical correlations also led to the assignment of the absolute configuration of 1beta,10alpha-epoxy-salonitenolide (13), a previously isolated natural product. The cytotoxic activities of some compounds were determined against A549 and MCF-7 tumor cell lines. The esterified germacranolides 2-6 were selectively cytotoxic against the MCF-7 breast cancer cell line.
The wild taxa utilized as vegetables in Sicily (Italy): a traditional component of the Mediterranean diet
2018
Background: Wild vegetables in the Mediterranean Basin are still often consumed as a part of the diet and, in particular, there is a great tradition regarding their use in Sicily.In this study, an ethnobotanical field investigation was carried out to (a) identify the wild native taxa traditionally gathered and consumed as vegetables in Sicily, comparing the collected ethnobotanical data with those of other countries that have nominated the Mediterranean diet for inclusion in the UNESCO Representative List of the Intangible Cultural Heritage of Humanity and (b) highlight new culinary uses of these plants.Methods: Interviews were carried out in 187 towns and villages in Sicily between 2005 an…
Adaptive physiological water conservation explains hypertension and muscle catabolism in experimental chronic renal failure
2021
Abstract Aim We have reported earlier that a high salt intake triggered an aestivation‐like natriuretic‐ureotelic body water conservation response that lowered muscle mass and increased blood pressure. Here, we tested the hypothesis that a similar adaptive water conservation response occurs in experimental chronic renal failure. Methods In four subsequent experiments in Sprague Dawley rats, we used surgical 5/6 renal mass reduction (5/6 Nx) to induce chronic renal failure. We studied solute and water excretion in 24‐hour metabolic cage experiments, chronic blood pressure by radiotelemetry, chronic metabolic adjustment in liver and skeletal muscle by metabolomics and selected enzyme activity…
No association between Helicobacter pylori infection and gastrointestinal complaints in a large cohort of symptomatic children.
2019
Aim This Polish study estimated the prevalence of the Helicobacter pylori infection in symptomatic children aged 3-18 and investigated its association with gastrointestinal complaints. Methods We prospectively enrolled 1984 children (54% female) with a mean age of 9.5 ± 4.1 years, from Silesia, Poland, for the Good Diagnosis Treatment Life screening programme from 2009 to 2016. They underwent a 13 C-isotope-labelled urea breath test (UBT) to assess their Helicobacter pylori status, making this the biggest Polish study to use this approach. Further analysis included parental-reported gastrointestinal symptoms and standard deviation scores (SDS) of anthropometric measurements. Results The Hel…
Test-and-treat strategy for Helicobacter pylori (HP) infection in older patients.
2010
Abstract Despite Helicobacter pylori (HP) infection is highly prevalent in older populations, low rates of HP diagnosis and eradication are reported in older persons, even in geriatric wards. We aim to evaluate the results of a HP-eradicating program in a sample of older patients in relation to dyspeptic symptoms and to endoscopic findings. A pool of 140 subjects (female/ale = 86/54, mean age 68.6 ± 5.4 years) with positive C 13 -urea breath test were recruited, clinically evaluated to investigate the presence and characteristics of dyspepsia and abdominal pain, and underwent gastric endoscopic examination. HP-eradication was obtained in 87.9% of subjects with first-line triple therapy, reg…
Outcome of lower-risk patients with myelodysplastic syndromes without 5q deletion after failure of erythropoiesis-stimulating agents
2017
Purpose Most anemic patients with non-deleted 5q lower-risk myelodysplastic syndromes (MDS) are treated with erythropoiesis-stimulating agents (ESAs), with a response rate of approximately 50%. Second-line treatments, including hypomethylating agents (HMAs), lenalidomide (LEN), and investigational drugs, may be used after ESA failure in some countries, but their effect on disease progression and overall survival (OS) is unknown. Here, we analyzed outcome after ESA failure and the effect of second-line treatments. Patients and Methods We examined an international retrospective cohort of 1,698 patients with non-del(5q) lower-risk MDS treated with ESAs. Results Erythroid response to ESAs was 6…
Early Skin Toxicity as a Predictive Factor for Tumor Control in Hepatocellular Carcinoma Patients Treated with Sorafenib.
2010
Abstract Introduction. Sorafenib is an oral multikinase inhibitor that targets Raf kinase and receptor tyrosine kinases and has led to a longer median overall survival (OS) time and time to progression (TTP) in patients with advanced hepatocellular carcinoma (HCC). This study was conducted to assess the link between the antitumor efficacy of sorafenib and its early cutaneous side effects in advanced HCC patients. Materials and Methods. All patients received 800 mg daily of sorafenib until progression or unacceptable toxicities. We retrospectively analyzed the incidence of rash and hand–foot skin reactions (HFSR) during the first month of treatment, comparing tumor control (partial response …
Evaluation of drug-metabolizing and functional competence of human hepatocytes incubated under hypothermia in different media for clinical infusion.
2008
Hepatocyte transplantation has been proposed as a method to support patients with liver insufficiency. Key factors for clinical cell transplantation to progress is to prevent hepatocyte damage, loss of viability and cell functionality, factors that depend on the nature of the tissue used for isolation to a large extent. The main sources of tissue for hepatocyte isolation are marginal livers that are unsuitable for transplantation, and segments from reduced cadaveric grafts. Hepatocellular transplantation requires infusing human hepatocytes in Suspension over a period of minutes to hours. The beneficial effect of hypothermic preservation of hepatocytes in infusion medium has been reported, b…