We present synthetic experiments of lactic acid (LA) polycondensation to produce poly(lactic acid) (PLA) as well as kinetic modeling calculations that capture the polymer molecular weight increase with time, given the initial concentrations. Tin-octoate-catalyzed polycondensation of (D,L)- or L-lactic acid was carried out in pre-dried toluene after azeotropic dehydration for 48-120 h at 130-137 °C. The polymerization was optimized by varying lactic acid and catalyst concentrations as well as the temperature.
View Article and Find Full Text PDFWe study partitions (equitable, externally equitable, or other) of graphs that describe physico-chemical systems at the atomic or molecular level; provide examples that show how these partitions are intimately related with symmetries of the systems; and discuss how such a link can further lead to insightful relations with the systems' physical and chemical properties. We define a particular kind of graph partition, which we call Chemical Equitable Partition (CEP), accounting for chemical composition as well as connectivity and associate it with a quantitative measure of information reduction that accompanies its derivation. These concepts are applied to model molecular and crystalline solid systems, illustrating their potential as a means to classify atoms according to their chemical or crystallographic role.
View Article and Find Full Text PDFOur work concerns the study of four candidate drug compounds of the terpenoid family, found as essential oil ingredients in species of the Greek endemic flora, namely carvacrol, p-cymene, γ-terpinene, and thymol, via the simulation method of molecular dynamics. Aquatic solutions of each compound, as well as a solution of all four together in realistic (experimental) proportions, are simulated at atmospheric pressure and 37 °C using an OPLS force field combined with TIP3P water. As verified, all four compounds exhibit a strong tendency to phase-separate, thereby calling for the use of carrier molecules as aids for the drug to circulate in the blood and enter the cells.
View Article and Find Full Text PDFSingle nucleotide polymorphisms (SNPs) are genetic variations which can play a vital role in the study of human health. SNP studies are often used to identify point mutations that are associated with diseases. Arkadia (RNF111) is an E3 ubiquitin ligase that enhances transforming growth factor-beta (TGF-) signaling by targeting negative regulators for degradation.
View Article and Find Full Text PDFRationale & Objective: Current recommendations suggest the use of ambulatory blood pressure monitoring (ABPM) as the gold standard for hypertension diagnosis and management in hemodialysis patients. This study assesses the accuracy of peridialytic, intradialytic, and scheduled interdialytic recordings in detecting abnormally elevated 44-hour interdialytic blood pressure (BP).
Study Design: Diagnostic test study.
Background: The pathophysiology of renal disease progression in autosomal-dominant polycystic kidney disease (ADPKD) involves not only cystogenesis but also endothelial dysfunction, leading to the activation of inflammatory and fibrotic pathways. This study evaluated the levels of biomarkers related to osmoregulation, immune system activation, and tubular injury in ADPKD patients with impaired or preserved renal function.
Methods: This study included 26 ADPKD patients with modestly impaired renal function (estimated glomerular filtration rate [eGFR] 45-70 mL/min/1.
Background: Intradialytic hypertension occurs in 5-15% of hemodialysis patients and is associated with increased cardiovascular risk, but the responsible mechanisms remain unknown. This study examined the effects of nebivolol and irbesartan on ambulatory central blood pressure (BP), arterial stiffness, and wave-reflection parameters in patients with intradialytic hypertension.
Methods: This is a prespecified analysis of a single-blind, randomized, cross-over study in 38 hemodialysis patients with intradialytic hypertension.
Heart failure (HF), hypertension, and abnormal nocturnal blood pressure dipping are highly prevalent in hemodialysis patients. Atrial fibrillation (AF) and HF might be important mediators for the association of abnormal dipping patterns with worse prognosis. Thus, the aim of this study is to investigate the association of dipping with mortality in hemodialysis patients and to assess the influence of AF and HF.
View Article and Find Full Text PDFBackground: Uncontrolled hypertension notwithstanding the use of at least three drugs or hypertension controlled with at least four drugs, the widely accepted definition of treatment-resistant hypertension (TRH), is considered as a common problem in the hemodialysis population. However, to date there is no estimate of the prevalence of this condition in hemodialysis patients.
Method: We estimated the prevalence of TRH by 44-h ambulatory BP monitoring (ABPM) in 506 hemodialysis patients in 10 renal units in Europe included in the registry of the European Renal and Cardiovascular Medicine (EURECAm,), a working group of the European Association, European Dialysis and Transplantation Association (ERA EDTA).
Background: Evidence suggests that the anti-aging protein a-Klotho is a central modulator of mineral homeostasis. Circulating a-Klotho exerts endocrine activity and has been implicated in the process of vascular calcification, which is accelerated in patients with chronic kidney disease (CKD) and portends an unfavorable overall prognosis. However, the role of a-Klotho in this process remains unclear.
View Article and Find Full Text PDFAutosomal-dominant polycystic kidney disease (ADPKD) is the most prevalent inherited kidney disease, characterized by growth of bilateral renal cysts, hypertension, and multiple extrarenal complications that eventually can lead to renal failure. It is caused by mutations in PKD1 or PKD2 genes encoding the proteins polycystin-1 and polycystin-2, respectively. Over the past few years, studies investigating the role of primary cilia and polycystins, present not only on the surface of renal tubular cells but also on vascular endothelial cells, have advanced our understanding of the pathogenesis of ADPKD and have shown that mechanisms other than cyst formation also contribute to renal functional decline in this disease.
View Article and Find Full Text PDFIncreased blood pressure (BP) variability (BPV) is associated with high cardiovascular risk in hemodialysis. Studies on the effects of antihypertensive drugs on BPV in hemodialysis are scarce. This study examines the effects of nebivolol and irbesartan on short-term BPV in patients with intradialytic hypertension.
View Article and Find Full Text PDFBackground: Long-term pre-dialysis blood pressure variability (BPV) in haemodialysis patients is associated with increased cardiovascular risk. The association of the main haemodynamic culprit in dialysis, that is, short-term BPV, with outcomes has not been investigated. We examine the prognostic role of short-term BPV for mortality and cardiovascular events in this population.
View Article and Find Full Text PDFThe SAFT-γ Mie group-contribution equation of state [ Papaioannou J. Chem. Phys.
View Article and Find Full Text PDFObjectives: Intradialytic hypertension is estimated at 5-15% of hemodialysis patients and is associated with poor prognosis. Studies on therapeutic interventions for this entity are extremely few. We aimed to evaluate the effects of nebivolol and irbesartan on peridialytic, intradialytic, and ambulatory BP in patients with intradialytic hypertension.
View Article and Find Full Text PDFBackground: Population-specific consensus documents recommend that the diagnosis of hypertension in haemodialysis patients be based on 48-h ambulatory blood pressure (ABP) monitoring. However, until now there is just one study in the USA on the prevalence of hypertension in haemodialysis patients by 44-h recordings. Since there is a knowledge gap on the problem in European countries, we reassessed the problem in the European Cardiovascular and Renal Medicine working group Registry of the European Renal Association-European Dialysis and Transplant Association.
View Article and Find Full Text PDFKidney Blood Press Res
October 2018
Background/aims: The pathophysiology of renal disease progression in autosomal dominant polycystic disease (ADPKD) is largely unknown. Recent evidence suggests microvascular dysfunction leading to renal ischemia, as an additional pathway for renal function decline. This study examined the levels of serum Fas ligand (FasL), serum myostatin and urine transforming growth factor-beta 1 (TGF-β1) and their association with markers of endothelial dysfunction, in ADPKD patients with preserved or impaired renal function.
View Article and Find Full Text PDFBackground: Endothelial dysfunction leading to unbalanced vasoconstriction and ischemia of renal parenchyma is increasingly proposed as an alternative pathway of renal damage in autosomal dominant polycystic kidney disease (ADPKD). However, human studies investigating the evolution of such phenomena are limited. This study investigated the levels of emerging biomarkers of endothelial function, angiogenesis and hypoxia, in ADPKD patients with different renal function.
View Article and Find Full Text PDFNephrol Dial Transplant
November 2018
Hypertension and progressive decline of renal function are among the common clinical manifestations in autosomal dominant polycystic kidney disease (ADPKD). At present, cyst formation in ADPKD patients is still considered the main pathogenic mechanism for the onset of these manifestations. However, the presence of polycystins in the vessels and the cilia of the endothelial cells and vascular smooth muscle cells, as well as development of hypertension prior to renal function decline and its prognostic role for the latter, indicate that polycystins may have an important role for endothelial damage in several vascular beds.
View Article and Find Full Text PDFPurpose: Sodium polystyrene sulfonate (SPS) is a cation-exchanging resin that has been widely used for several decades as first-line therapy of mild chronic hyperkalemia in patients with chronic kidney disease (CKD). However, evidence to prove the long-term tolerability and efficacy of SPS for the treatment of this condition is still missing.
Methods: In this retrospective, observational study, we enrolled 26 outpatients with stages 3-4 CKD who received oral therapy with low-dose SPS for mild chronic hyperkalemia in the Outpatient Nephrology clinic of our Department during 2010-2016.
Voice performance is an inextricable key factor of everyday life. Obviously, the deterioration of voice quality can cause various problems to human communication and can therefore reduce the performance of social skills (relevant to voice). The deterioration could be originated from changes inside the system of the vocal tract and larynx.
View Article and Find Full Text PDFArterial stiffness and augmentation of aortic blood pressure (BP) measured in office are known cardiovascular risk factors in hemodialysis patients. This study examines the prognostic significance of ambulatory brachial BP, central BP, pulse wave velocity (PWV), and heart rate-adjusted augmentation index [AIx(75)] in this population. A total of 170 hemodialysis patients underwent 48-hour ambulatory monitoring with Mobil-O-Graph-NG during a standard interdialytic interval and followed-up for 28.
View Article and Find Full Text PDF