51 research outputs found
Multiplex Amplification Refractory Mutation System Polymerase Chain Reaction (ARMS-PCR) for diagnosis of natural infection with canine distemper virus
<p>Abstract</p> <p>Background</p> <p>Canine distemper virus (CDV) is present worldwide and produces a lethal systemic infection of wild and domestic <it>Canidae</it>. Pre-existing antibodies acquired from vaccination or previous CDV infection might interfere the interpretation of a serologic diagnosis method. In addition, due to the high similarity of nucleic acid sequences between wild-type CDV and the new vaccine strain, current PCR derived methods cannot be applied for the definite confirmation of CD infection. Hence, it is worthy of developing a simple and rapid nucleotide-based assay for differentiation of wild-type CDV which is a cause of disease from attenuated CDVs after vaccination. High frequency variations have been found in the region spanning from the 3'-untranslated region (UTR) of the matrix (M) gene to the fusion (F) gene (designated M-F UTR) in a few CDV strains. To establish a differential diagnosis assay, an amplification refractory mutation analysis was established based on the highly variable region on M-F UTR and F regions.</p> <p>Results</p> <p>Sequences of frequent polymorphisms were found scattered throughout the M-F UTR region; the identity of nucleic acid between local strains and vaccine strains ranged from 82.5% to 93.8%. A track of AAA residue located 35 nucleotides downstream from F gene start codon highly conserved in three vaccine strains were replaced with TGC in the local strains; that severed as target sequences for deign of discrimination primers. The method established in the present study successfully differentiated seven Taiwanese CDV field isolates, all belonging to the Asia-1 lineage, from vaccine strains.</p> <p>Conclusions</p> <p>The method described herein would be useful for several clinical applications, such as confirmation of nature CDV infection, evaluation of vaccination status and verification of the circulating viral genotypes.</p
On the constraints violation in forward dynamics of multibody systems
It is known that the dynamic equations of motion for constrained mechanical multibody systems are frequently formulated using the Newton-Euler’s approach, which is augmented with the acceleration constraint equations. This formulation results in the establishment of a mixed set of partial differential and algebraic equations, which are solved in order to predict the dynamic behavior of general multibody systems. The classical resolution of the equations of motion is highly prone to constraints violation because the position and velocity constraint equations are not fulfilled. In this work, a general and comprehensive methodology to eliminate the constraints violation at the position and velocity levels is offered. The basic idea of the described approach is to add corrective terms to the position and velocity vectors with the intent to satisfy the corresponding kinematic constraint equations. These corrective terms are evaluated as function of the Moore-Penrose generalized inverse of the Jacobian matrix and of the kinematic constraint equations. The described methodology is embedded in the standard method to solve the equations of motion based on the technique of Lagrange multipliers. Finally, the effectiveness of the described methodology is demonstrated through the dynamic modeling and simulation of different planar and spatial multibody systems. The outcomes in terms of constraints violation at the position and velocity levels, conservation of the total energy and computational efficiency are analyzed and compared with those obtained with the standard Lagrange multipliers method, the Baumgarte stabilization method, the augmented Lagrangian formulation, the index-1 augmented Lagrangian and the coordinate partitioning method.The first author expresses his gratitude to the Portuguese Foundation for Science and Technology through the PhD grant (PD/BD/114154/2016). This work has been supported by the Portuguese Foundation for Science and Technology with the reference project UID/EEA/04436/2013, by FEDER funds through the COMPETE 2020 – Programa Operacional Competitividade e Internacionalização (POCI) with the reference project POCI-01-0145-FEDER-006941.info:eu-repo/semantics/publishedVersio
Repositioning of the global epicentre of non-optimal cholesterol
High blood cholesterol is typically considered a feature of wealthy western countries1,2. However, dietary and behavioural determinants of blood cholesterol are changing rapidly throughout the world3 and countries are using lipid-lowering medications at varying rates. These changes can have distinct effects on the levels of high-density lipoprotein (HDL) cholesterol and non-HDL cholesterol, which have different effects on human health4,5. However, the trends of HDL and non-HDL cholesterol levels over time have not been previously reported in a global analysis. Here we pooled 1,127 population-based studies that measured blood lipids in 102.6 million individuals aged 18 years and older to estimate trends from 1980 to 2018 in mean total, non-HDL and HDL cholesterol levels for 200 countries. Globally, there was little change in total or non-HDL cholesterol from 1980 to 2018. This was a net effect of increases in low- and middle-income countries, especially in east and southeast Asia, and decreases in high-income western countries, especially those in northwestern Europe, and in central and eastern Europe. As a result, countries with the highest level of non-HDL cholesterol—which is a marker of cardiovascular risk—changed from those in western Europe such as Belgium, Finland, Greenland, Iceland, Norway, Sweden, Switzerland and Malta in 1980 to those in Asia and the Pacific, such as Tokelau, Malaysia, The Philippines and Thailand. In 2017, high non-HDL cholesterol was responsible for an estimated 3.9 million (95% credible interval 3.7 million–4.2 million) worldwide deaths, half of which occurred in east, southeast and south Asia. The global repositioning of lipid-related risk, with non-optimal cholesterol shifting from a distinct feature of high-income countries in northwestern Europe, north America and Australasia to one that affects countries in east and southeast Asia and Oceania should motivate the use of population-based policies and personal interventions to improve nutrition and enhance access to treatment throughout the world.</p
Rising rural body-mass index is the main driver of the global obesity epidemic in adults
Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities 1,2 . This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity 3�6 . Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55 of the global rise in mean BMI from 1985 to 2017�and more than 80 in some low- and middle-income regions�was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing�and in some countries reversal�of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories. © 2019, The Author(s)
Repositioning of the global epicentre of non-optimal cholesterol
High blood cholesterol is typically considered a feature of wealthy western countries1,2. However, dietary and behavioural determinants of blood cholesterol are changing rapidly throughout the world3 and countries are using lipid-lowering medications at varying rates. These changes can have distinct effects on the levels of high-density lipoprotein (HDL) cholesterol and non-HDL cholesterol, which have different effects on human health4,5. However, the trends of HDL and non-HDL cholesterol levels over time have not been previously reported in a global analysis. Here we pooled 1,127 population-based studies that measured blood lipids in 102.6 million individuals aged 18 years and older to estimate trends from 1980 to 2018 in mean total, non-HDL and HDL cholesterol levels for 200 countries. Globally, there was little change in total or non-HDL cholesterol from 1980 to 2018. This was a net effect of increases in low- and middle-income countries, especially in east and southeast Asia, and decreases in high-income western countries, especially those in northwestern Europe, and in central and eastern Europe. As a result, countries with the highest level of non-HDL cholesterol�which is a marker of cardiovascular risk�changed from those in western Europe such as Belgium, Finland, Greenland, Iceland, Norway, Sweden, Switzerland and Malta in 1980 to those in Asia and the Pacific, such as Tokelau, Malaysia, The Philippines and Thailand. In 2017, high non-HDL cholesterol was responsible for an estimated 3.9 million (95 credible interval 3.7 million�4.2 million) worldwide deaths, half of which occurred in east, southeast and south Asia. The global repositioning of lipid-related risk, with non-optimal cholesterol shifting from a distinct feature of high-income countries in northwestern Europe, north America and Australasia to one that affects countries in east and southeast Asia and Oceania should motivate the use of population-based policies and personal interventions to improve nutrition and enhance access to treatment throughout the world. © 2020, The Author(s), under exclusive licence to Springer Nature Limited
Phenotypic changes in the Japanese encephalitis virus after one passage in Neuro-2a cells: Generation of attenuated strains of the virus
Live attenuated strains of the Japanese encephalitis (JE) virus are known to form in various cultured cells. In this study, we selected attenuated JE virus variants by passing the parent virus strains once through Neuro-2a cells, showing that the selection intensity ranged 2-1000-fold after infection for 3 d. The selection of attenuated variants appeared in association with mutations on the envelope (E) glycoprotein. This is likely determined by the differential binding abilities of specific E proteins with highly sulfated glycosaminoglycans on the cell. surface. A plaque-purification method showed that Neuro-2a-selected variants were usually less neurovirulent, Leading to a longer survival time of intracerebrally inoculated mice. Specific selected variants (mostly with the small-plaque phenotype) were shown to be more efficient at replication in Vero cells and less virulent, particularly those with substitution of the E-138 (Glu -> Lys) residue. As a result, most, if not all, Low-virulent variants were generated in a relatively short time, all. which have the potential to be live-attenuated vaccine candidates of the JE virus. (c) 2007 Elsevier Ltd. All rights reserved
Enzyme-linked Immunosorbent assays using novel Japanese encephalitis virus antigen improve the accuracy of clinical diagnosis of flavivirus infections
The cross-reactive antibodies induced by flavivirus infections confound serodiagnosis and pathogenesis, especially in secondary infections caused by antigenically closely related yet distinct flaviviruses. The envelope (E) glycoprotein fusion peptide contains immunodominant cross-reactive determinants. Using a recombinant Japanese encephalitis virus (JEV) premembrane and E expression plasmid producing JEV virus-like particles (VLPs), dramatic reductions in cross-reactivity were produced by the G106K-L107D (KD) double-mutant VLP against a panel of flavivirus murine monoclonal antibodies. Human serum panels from patients with recent flavivirus infections were analyzed to compare the accuracy of JEV wild-type (WT) and KD VLPs as serodiagnostic antigens in enzyme-linked immunosorbent assays. Statistical analysis demonstrated significant differences in assay performances for accurate determination of current JEV infections between WT and KD antigens by detecting immunoglobulin M antibodies at a serum dilution of 1: 4,000 (likelihood ratios = 2.74 [WT] and 22 [KD]). The application and continued development of cross-reactivity-reduced antigens should improve both flavivirus infection serodiagnosis and estimates of disease burden
Protein sub-fractions and amino acid profiles of rumen-undegradable protein in dairy cows from soybean, cottonseed and fish meals
The aim of this study was to investigate the degradability and the amino acid content of the ruminal undegradable protein in dairy cows from soybean meal, cottonseed meal and fish meal. Three 600 kg ruminally fistulated Holstein dry dairy cows were used for in situ incubations. The rumen protein degradability of soybean meal, fish meal and cottonseed meal at rumen outflow rate of 8% were 63.47, 37.71 and 82.10%, respectively. From the SDS-PAGE pattern and densitometric scanning, the basic sub-unit of glycinin in soybean meal, as well as most sub-fractions of fish meal protein were not completely degraded after 24 h incubation, whereas the protein of cottonseed meal was almost completely degraded. However, the in vitro digestibility of the undegradable protein from soybean meal and fish meal were higher than that from cottonseed meal. In addition, the amino acid content of the ruminal undegraded proteins differs from that of the original feed consumed by cows. (C) 1999 Elsevier Science B.V. All rights reserved
High antibody prevalence in an unconventional ecosystem is related to circulation of a low-virulent strain of Japanese encephalitis virus
Liu-Chiu islet, a relatively isolated ecosystem that is free of rice cultivation, has long considered free of Japanese encephalitis (JE). However, a new strain (T1P1) of JE virus was isolated from the mosquito, Armigeres subalbatus, and a rather broad distribution of neutralizing antibody has been reported on the islet, suggesting that the circulating virus could be an attenuated strain. In an assessment on 2 19 blood samples obtained from residents of Liu-Chiu islet, the positive rate of JEV-specific IgM antibodies decreased with age while that of neutralizing antibodies increased with age. Both antibodies were mainly responsive to the T1P1 strain since higher positive rates and titers of specific neutralizing antibodies are shown in this investigation. Importantly, the T1P1 strain is herein characterized as being broader in neutralizing virus strains, stable in genetic traits, and productive in Vero cells. Taken together, the JE virus strain endemically circulating on Liu-Chiu islet may have served as a natural form of a live-attenuated vaccine. As a result, it possibly can be utilized as a new and effective vaccine candidate in the future. (c) 2006 Elsevier Ltd. All rights reserved
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