161 research outputs found
A Three-Dimensional Numerical Study of Wave Induced Currents in the Cetraro Harbour Coastal Area (Italy)
In this paper we propose a three-dimensional numerical study of the coastal currents produced by the wave motion in the area opposite the Cetraro harbour (Italy), during the most significant wave event for the coastal sediment transport. The aim of the present study is the characterization of the current patterns responsible for the siltation that affects the harbour entrance area and the assessment of a project solution designed to limit this phenomenon. The numerical simulations are carried out by a three-dimensional non-hydrostatic model that is based on the Navier–Stokes equations expressed in integral and contravariant form on a time-dependent curvilinear coordinate system, in which the vertical coordinate moves in order to follow the free surface variations.
The numerical simulations are carried out in two different geometric configurations: a present configuration, that reproduces the geometry of the coastal defence structures currently present in the
harbour area and a project configuration, which reproduces the presence of a breakwater designed to modify the coastal currents in the area opposite the harbour entrance
A review of oxidative stress products and related genes in early alzheimer's disease
Oxidative stress is associated with the progression of Alzheimer's disease (AD). Reactive oxygen species can modify lipids, DNA, RNA, and proteins in the brain. The products of their peroxidation and oxidation are readily detectable at incipient stages of disease. Based on these oxidation products, various biomarker-based strategies have been developed to identify oxidative stress levels in AD. Known oxidative stress-related biomarkers include lipid peroxidation products F2-isoprostanes, as well as malondialdehyde and 4-hydroxynonenal which both conjugate to specific amino acids to modify proteins, and DNA or RNA oxidation products 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 8-hydroxyguanosine (8-OHG), respectively. The inducible enzyme heme oxygenase type 1 (HO-1) is found to be upregulated in response to oxidative stress-related events in the AD brain. While these global biomarkers for oxidative stress are associated with early-stage AD, they generally poorly differentiate from other neurodegenerative disorders that also coincide with oxidative stress. Redox proteomics approaches provided specificity of oxidative stress-associated biomarkers to AD pathology by the identification of oxidatively damaged pathology-specific proteins. In this review, we discuss the potential combined diagnostic value of these reported biomarkers in the context of AD and discuss eight oxidative stress-related mRNA biomarkers in AD that we newly identified using a transcriptomics approach. We review these genes in the context of their reported involvement in oxidative stress regulation and specificity for AD. Further research is warranted to establish the protein levels and their functionalities as well as the molecular mechanisms by which these potential biomarkers are involved in regulation of oxidative stress levels and their potential for determination of oxidative stress and disease status of AD patients
Characterization of insulin-degrading enzyme-mediated cleavage of Aβ in distinct aggregation states
To enhance our understanding of the potential therapeutic utility of insulin-degrading enzyme (IDE) in Alzheimer's disease (AD), we studied in vitro IDE-mediated degradation of different amyloid-beta (Aβ) peptide aggregation states. Our findings show that IDE activity is driven by the dynamic equilibrium between Aβ monomers and higher ordered aggregates. We identify Met35-Val36 as a novel IDE cleavage site in the Aβ sequence and show that Aβ fragments resulting from IDE cleavage form non-toxic amorphous aggregates. These findings need to be taken into account in therapeutic strategies designed to increase Aβ clearance in AD patients by modulating IDE activity
3,5-Diiodo-L-thyronine activates brown adipose tissue thermogenesis in hypothyroid rats
3,5-Diiodo-l-thyronine (T2), a thyroid hormone derivative, is capable of increasing energy expenditure, as well as preventing high fat diet-induced overweight and related metabolic dysfunction. Most studies to date on T2 have been carried out on liver and skeletal muscle. Considering the role of brown adipose tissue (BAT) in energy and metabolic homeostasis, we explored whether T2 could activate BAT thermogenesis. Using euthyroid, hypothyroid, and T2-treated hypothyroid rats (all maintained at thermoneutrality) in morphological and functional studies, we found that hypothyroidism suppresses the maximal oxidative capacity of BAT and thermogenesis, as revealed by reduced mitochondrial content and respiration, enlarged cells and lipid droplets, and increased number of unilocular cells within the tissue. In vivo administration of T2 to hypothyroid rats activated BAT thermogenesis and increased the sympathetic innervation and vascularization of tissue. Likewise, T2 increased BAT oxidative capacity in vitro when added to BAT homogenates from hypothyroid rats. In vivo administration of T2 to hypothyroid rats enhanced mitochondrial respiration. Moreover, UCP1 seems to be a molecular determinant underlying the effect of T2 on mitochondrial thermogenesis. In fact, inhibition of mitochondrial respiration by GDP and its reactivation by fatty acids were greater in mitochondria from T2-treated hypothyroid rats than untreated hypothyroid rats. In vivo administration of T2 led to an increase in PGC-1α protein levels in nuclei (transient) and mitochondria (longer lasting), suggesting a coordinate effect of T2 in these organelles that ultimately promotes net activation of mitochondrial biogenesis and BAT thermogenesis. The effect of T2 on PGC-1α is similar to that elicited by triiodothyronine. As a whole, the data reported here indicate T2 is a thyroid hormone derivative able to activate BAT thermogenesis
Studies of Complex Biological Systems with Applications to Molecular Medicine: The Need to Integrate Transcriptomic and Proteomic Approaches
Omics approaches to the study of complex biological systems with potential applications to molecular medicine are attracting great interest in clinical as well as in basic biological research. Genomics, transcriptomics and proteomics are characterized by the lack of an a priori definition of scope, and this gives sufficient leeway for investigators (a) to discern all at once a globally altered pattern of gene/protein expression and (b) to examine the complex interactions that regulate entire biological processes. Two popular platforms in “omics” are DNA microarrays, which measure messenger RNA transcript levels, and proteomic analyses, which identify and quantify proteins. Because of their intrinsic strengths and weaknesses, no single approach can fully unravel the complexities of fundamental biological events. However, an appropriate combination of different tools could lead to integrative analyses that would furnish new insights not accessible through one-dimensional datasets. In this review, we will outline some of the challenges associated with integrative analyses relating to the changes in metabolic pathways that occur in complex pathophysiological conditions (viz. ageing and altered thyroid state) in relevant metabolically active tissues. In addition, we discuss several new applications of proteomic analysis to the investigation of mitochondrial activity
Differential Effects of 3,5-Diiodo-L-Thyronine and 3,5,3'-Triiodo-L-Thyronine On Mitochondrial Respiratory Pathways in Liver from Hypothyroid Rats.
Both 3,5-diiodo-L-thyronine (3,5-T2) and 3,5,3'-triiodo-L-tyronine (T3) affect energy metabolism having mitochondria as a major target. However, the underlying mechanisms are poorly understood. Here, using a model of chemically induced hypothyroidism in male Wistar rats, we investigated the effect of administration of either 3,5-T2 or T3 on liver oxidative capacity through their influence on mitochondrial processes including: proton-leak across the mitochondrial inner membrane; complex I-, complex II- and glycerol-3-phosphate-linked respiratory pathways; respiratory complex abundance and activities as well as individual complex aggregation into supercomplexes. Background/Aims: Both 3,5-diiodo-L-thyronine (3,5-T2) and 3,5,3'-triiodo-L-tyronine (T3) affect energy metabolism having mitochondria as a major target. However, the underlying mechanisms are poorly understood. Here, using a model of chemically induced hypothyroidism in male Wistar rats, we investigated the effect of administration of either 3,5-T2 or T3 on liver oxidative capacity through their influence on mitochondrial processes including: proton-leak across the mitochondrial inner membrane; complex I-, complex II- and glycerol-3-phosphate-linked respiratory pathways; respiratory complex abundance and activities as well as individual complex aggregation into supercomplexes. Methods: Hypothyroidism was induced by propylthiouracil and iopanoic acid; 3,5-T2 and T3 were intraperitoneally administered at 25 and 15 μg/100 g BW for 1 week, respectively. Resulting alterations in mitochondrial function were studied by combining respirometry, Blue Native-PAGE followed by in-gel activity, and Western blot analyses. Results: Administration of 3,5-T2 and T3 to hypothyroid (hypo) rats enhanced mitochondrial respiration rate with only T3 effectively stimulating proton-leak (450% vs. Hypo). T3 significantly enhanced complex I (+145% vs. Hypo), complex II (+66% vs. Hypo), and glycerol-3 phosphate dehydrogenase (G3PDH)-linked oxygen consumptions (about 6- fold those obtained in Hypo), while 3,5-T2 administration selectively restored Euthyroid values of complex II- and increased G3PDH- linked respiratory pathways (+165% vs. Hypo). The mitochondrial abundance of all respiratory complexes and of G3PDH was increased by T3 administration whereas 3,5-T2 only increased complex V and G3PDH abundance. 3,5-T2 enhanced complex I and complex II in gel activities with less intensity than did T3, and T3 also enhanced the activity of all other respiratory complexes tested. In addition, only T3 enhanced individual respiratory component complex assembly into supercomplexes. Conclusions: The reported data highlight novel molecular mechanisms underlying the effect elicited by iodothyronine administration to hypothyroid rats on mitochondrial processes related to alteration in oxidative capacity in the liver. The differential effects elicited by the two iodothyronines indicate that 3,5-T2, by influencing the kinetic properties of specific mitochondrial respiratory pathways, would promote a rapid response of the organelle, while T3, by enhancing the abundance of respiratory chain component and favoring the organization of respiratory chain complex in supercomplexes, would induce a slower and prolonged response of the organelle
Sex-Specific Association of Left Ventricular Hypertrophy With Rheumatoid Arthritis
Objectives: Clinical expression of rheumatoid arthritis (RA) varies by gender, but whether cardiovascular disease (CVD) is gender related in RA is unknown. Left ventricular (LV) hypertrophy (LVH) is a hallmark of CVD in RA patients. We investigated whether the association of LVH with RA is gender driven.Methods: Consecutive outpatients with established RA underwent echocardiography with measurement of LVH at baseline and one follow-up. All participants had no prior history of CVD or diabetes mellitus. We assessed CVD risk factors associated with LVH at follow-up, including sex, age, arterial blood pressure, and body mass index (BMI). We also evaluated inflammatory markers, autoimmunity, disease activity, and the use of RA medications as predictors of LVH.Results: We recruited 145 RA patients (121 females, 83%) and reassessed them after a median (interquartile range) of 36 months (24–50). At baseline, women were more dyslipidemic but otherwise had fewer CVD risk factors than men, including less prevalent smoking habit and hypertension, and smaller waist circumference. At follow-up, we detected LVH in 42/145 (44%) RA patients. LV mass significantly increased only in women. In multiple Cox regression analysis, women with RA had the strongest association with LVH, independently from the presence of CVD risk factors (OR, 6.56; 95% CI, 1.34–30.96) or RA-specific characteristics (OR, 5.14; 95% CI, 1.24–21.34). BMI was also significantly and independently associated with LVH.Conclusion: Among established RA patients, women carry the highest predisposition for LVH
Exercise with Energy Restriction as a Means of Losing Body Mass while Preserving Muscle Quality and Ameliorating Co-morbidities: Towards a Therapy for Obesity?
Exercise with Energy Restriction as a Means of Losing Body Mass while Preserving Muscle Quality and Ameliorating Co-morbidities: Towards a Therapy for Obesity?
Antonia Giacco1*, Elena Silvestri1*, Rosalba Senese2, Federica Cioffi1, Arianna Cuomo2, Assunta Lombardi3, Maria Moreno1, Antonia Lanni2 and Pieter de Lange()2
1Dipartimento di Science e Tecnologie, Università degli Studi del Sannio, Benevento, Italy
2Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania "Luigi Vanvitelli," Caserta, Italy
3Dipartimento di Biologia, Università degli Studi di Napoli "Federico II," Napoli, Italy
© The Authors
Abstract
Obesity and related co-morbidities are a major public health threat worldwide, and efforts to counteract obesity by means of physiological interventions are currently being explored and applied. Here we present an overview of the literature on the effect of dietary/exercise-based programs on loss of different components of body mass. We also discuss gain or lack of loss of lean mass in view of muscle quality maintenance, which is an important aspect to consider when employing weight-loss strategies to tackle obesity. By comparing results obtained in participants with mild to severe obesity with those obtained in lean participants, we highlight variations in the success of these interventions. Furthermore, we briefly address the observation that although certain interventions may not always affect body composition they can nevertheless ameliorate co-morbidities (insulin resistance, non-alcoholic fatty liver disease). Based on what is currently known, in this narrative review we include data from human and animal studies related to the process of unravelling the mechanisms underlying conservation of functional muscle mass
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