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1.
Mult Scler Relat Disord ; 65: 104022, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35816953

RESUMEN

BACKGROUND: Current guidelines recommend vaccination against SARS-CoV2 for people with multiple sclerosis (pwMS). The long-term review of the safety and effectiveness of COVID-19 vaccines in pwMS is limited. METHODS: Service re-evaluation. PwMS using the MS service at Barts Health National Health Service Trust were sent questionnaires via email to report symptoms following first and second COVID-19 vaccinations (n = 570). A retrospective review of electronic health records was conducted for clinical and safety data post-vaccination(s); cut-off was end of September 2021. Separate logistic regressions were carried out for symptoms experienced at each vaccination. Two sets of regressions were fitted with covariates: (i) Disease-modifying therapy type and (ii) patient characteristics for symptoms experienced. RESULTS: 193/570 pwMS responded. 184 pwMS had both vaccinations. 144 received the AZD1222 and 49 the BNT162b2 vaccine. 87% and 75% of pwMS experienced any symptoms at first and second vaccinations, respectively. The majority of symptoms resolved within a short timeframe. No severe adverse effects were reported. Two pwMS subsequently died; one due to COVID-19 and one due to aspiration pneumonia. Males were at a reduced risk of reporting symptoms at first vaccination. There was evidence that pwMS in certain treatment groups were at reduced risk of reporting symptoms at second vaccination only. CONCLUSIONS: Findings are consistent with our preliminary data. Symptoms post-vaccination were similar to the non-MS population and were mostly temporary. It is important to inform the MS community of vaccine safety data.


Asunto(s)
Vacunas contra la COVID-19 , COVID-19 , Esclerosis Múltiple , Vacuna BNT162 , COVID-19/prevención & control , Vacunas contra la COVID-19/efectos adversos , ChAdOx1 nCoV-19 , Humanos , Masculino , ARN Viral , SARS-CoV-2 , Medicina Estatal , Vacunación/efectos adversos
3.
JCO Oncol Pract ; 17(1): 41-51, 2021 01.
Artículo en Inglés | MEDLINE | ID: mdl-33405975

RESUMEN

PURPOSE: Feasibility assessments (FAs) are important to establish site capabilities to conduct clinical trials and their suitability for specific trials. However, current FA methods used by biotechnology and pharmaceutical (biotech-pharma) trial sponsors and contract research organizations (CROs) are costly, inefficient, unnecessarily burdensome, and resource intensive. These methods delay trial start-up, act as a barrier to site participation, and ultimately reduce timely patient access to clinical trials and novel treatments. METHODS: An ASCO Task Force was convened to assess the specific burdens and challenges with FAs and to develop recommendations to improve their efficiencies and effectiveness. Stakeholders (including trial sites, biotech-pharma sponsors, and CROs) provided insights into challenges and offered solutions through two surveys and an in-person meeting. The Task Force used the feedback to formulate consensus recommendations to improve FAs for oncology clinical trials. RESULTS: Three key recommendations were identified for application across all biotech-pharma sponsored trials: (1) implement a streamlined and uniform FA process across trials and sponsors; (2) minimize and standardize questions; and (3) leverage technology to centralize FAs, facilitate communications, and reduce redundancies. CONCLUSION: There is an urgency to improve the current FA process, which is costly, inconsistent, inefficient, labor intensive, and of uncertain effectiveness. All stakeholders stand to benefit from implementing these recommendations, which aim to minimize burdens and ensure that more trial sites and patients have timely access to oncology clinical trials. To have meaningful impact, adoption and consistent execution of these recommendations across all trials, sponsors, CROs, and sites are essential.


Asunto(s)
Oncología Médica , Neoplasias , Comités Consultivos , Ensayos Clínicos como Asunto , Estudios de Factibilidad , Humanos , Neoplasias/terapia , Encuestas y Cuestionarios
4.
Nat Commun ; 11(1): 6036, 2020 11 27.
Artículo en Inglés | MEDLINE | ID: mdl-33247130

RESUMEN

Human activities are transforming grassland biomass via changing climate, elemental nutrients, and herbivory. Theory predicts that food-limited herbivores will consume any additional biomass stimulated by nutrient inputs ('consumer-controlled'). Alternatively, nutrient supply is predicted to increase biomass where herbivores alter community composition or are limited by factors other than food ('resource-controlled'). Using an experiment replicated in 58 grasslands spanning six continents, we show that nutrient addition and vertebrate herbivore exclusion each caused sustained increases in aboveground live biomass over a decade, but consumer control was weak. However, at sites with high vertebrate grazing intensity or domestic livestock, herbivores consumed the additional fertilization-induced biomass, supporting the consumer-controlled prediction. Herbivores most effectively reduced the additional live biomass at sites with low precipitation or high ambient soil nitrogen. Overall, these experimental results suggest that grassland biomass will outstrip wild herbivore control as human activities increase elemental nutrient supply, with widespread consequences for grazing and fire risk.


Asunto(s)
Biomasa , Pradera , Herbivoria/fisiología , Nitrógeno/análisis , Fósforo/análisis , Intervalos de Confianza , Fertilizantes , Factores de Tiempo
5.
Nat Commun ; 10(1): 4981, 2019 10 31.
Artículo en Inglés | MEDLINE | ID: mdl-31672992

RESUMEN

Soil nitrogen mineralisation (Nmin), the conversion of organic into inorganic N, is important for productivity and nutrient cycling. The balance between mineralisation and immobilisation (net Nmin) varies with soil properties and climate. However, because most global-scale assessments of net Nmin are laboratory-based, its regulation under field-conditions and implications for real-world soil functioning remain uncertain. Here, we explore the drivers of realised (field) and potential (laboratory) soil net Nmin across 30 grasslands worldwide. We find that realised Nmin is largely explained by temperature of the wettest quarter, microbial biomass, clay content and bulk density. Potential Nmin only weakly correlates with realised Nmin, but contributes to explain realised net Nmin when combined with soil and climatic variables. We provide novel insights of global realised soil net Nmin and show that potential soil net Nmin data available in the literature could be parameterised with soil and climate data to better predict realised Nmin.

6.
Ecol Lett ; 22(7): 1136-1144, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-31074933

RESUMEN

Sodium is unique among abundant elemental nutrients, because most plant species do not require it for growth or development, whereas animals physiologically require sodium. Foliar sodium influences consumption rates by animals and can structure herbivores across landscapes. We quantified foliar sodium in 201 locally abundant, herbaceous species representing 32 families and, at 26 sites on four continents, experimentally manipulated vertebrate herbivores and elemental nutrients to determine their effect on foliar sodium. Foliar sodium varied taxonomically and geographically, spanning five orders of magnitude. Site-level foliar sodium increased most strongly with site aridity and soil sodium; nutrient addition weakened the relationship between aridity and mean foliar sodium. Within sites, high sodium plants declined in abundance with fertilisation, whereas low sodium plants increased. Herbivory provided an explanation: herbivores selectively reduced high nutrient, high sodium plants. Thus, interactions among climate, nutrients and the resulting nutritional value for herbivores determine foliar sodium biogeography in herbaceous-dominated systems.


Asunto(s)
Pradera , Herbivoria , Sodio , Adaptación Fisiológica , Animales , Nitrógeno , Plantas , Suelo
7.
Ecol Lett ; 22(6): 936-945, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-30884085

RESUMEN

Soil stores approximately twice as much carbon as the atmosphere and fluctuations in the size of the soil carbon pool directly influence climate conditions. We used the Nutrient Network global change experiment to examine how anthropogenic nutrient enrichment might influence grassland soil carbon storage at a global scale. In isolation, enrichment of nitrogen and phosphorous had minimal impacts on soil carbon storage. However, when these nutrients were added in combination with potassium and micronutrients, soil carbon stocks changed considerably, with an average increase of 0.04 KgCm-2  year-1 (standard deviation 0.18 KgCm-2  year-1 ). These effects did not correlate with changes in primary productivity, suggesting that soil carbon decomposition may have been restricted. Although nutrient enrichment caused soil carbon gains most dry, sandy regions, considerable absolute losses of soil carbon may occur in high-latitude regions that store the majority of the world's soil carbon. These mechanistic insights into the sensitivity of grassland carbon stocks to nutrient enrichment can facilitate biochemical modelling efforts to project carbon cycling under future climate scenarios.


Asunto(s)
Carbono , Suelo , Ecosistema , Nitrógeno , Nutrientes , Suelo/química
8.
Workplace Health Saf ; 66(5): 218-222, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-29121833

RESUMEN

This study investigated whether Fitbit devices can reduce sedentary behavior among employees in the workplace. Participants were asked to wear Fitbits during 8-hour work shifts, 5 days per week, for 8 weeks. They were instructed to stand at least once every 30 minutes throughout the workday. The goal of the study was to determine whether standing once every 30 minutes was a feasible strategy for reducing sedentary workplace behavior. On average, participants completed 36 of 40 workdays using Fitbits. The number of times participants stood during an 8-hour workday averaged 12 stands per day (maximum 16 stands per day). These results indicate that Fitbit technology is effective for recording and tracking interruptions in sitting time; however, to reduce sitting behavior, alternate approaches are required to motivate larger numbers of workers to participate.


Asunto(s)
Monitores de Ejercicio , Salud Laboral , Conducta Sedentaria , Lugar de Trabajo/psicología , Estudios de Factibilidad , Humanos , Postura , Factores de Tiempo
9.
Philos Trans A Math Phys Eng Sci ; 373(2054)2015 Nov 13.
Artículo en Inglés | MEDLINE | ID: mdl-26438276

RESUMEN

We present an approach to estimate the feedback from large-scale thawing of permafrost soils using a simplified, data-constrained model that combines three elements: soil carbon (C) maps and profiles to identify the distribution and type of C in permafrost soils; incubation experiments to quantify the rates of C lost after thaw; and models of soil thermal dynamics in response to climate warming. We call the approach the Permafrost Carbon Network Incubation-Panarctic Thermal scaling approach (PInc-PanTher). The approach assumes that C stocks do not decompose at all when frozen, but once thawed follow set decomposition trajectories as a function of soil temperature. The trajectories are determined according to a three-pool decomposition model fitted to incubation data using parameters specific to soil horizon types. We calculate litterfall C inputs required to maintain steady-state C balance for the current climate, and hold those inputs constant. Soil temperatures are taken from the soil thermal modules of ecosystem model simulations forced by a common set of future climate change anomalies under two warming scenarios over the period 2010 to 2100. Under a medium warming scenario (RCP4.5), the approach projects permafrost soil C losses of 12.2-33.4 Pg C; under a high warming scenario (RCP8.5), the approach projects C losses of 27.9-112.6 Pg C. Projected C losses are roughly linearly proportional to global temperature changes across the two scenarios. These results indicate a global sensitivity of frozen soil C to climate change (γ sensitivity) of -14 to -19 Pg C °C(-1) on a 100 year time scale. For CH4 emissions, our approach assumes a fixed saturated area and that increases in CH4 emissions are related to increased heterotrophic respiration in anoxic soil, yielding CH4 emission increases of 7% and 35% for the RCP4.5 and RCP8.5 scenarios, respectively, which add an additional greenhouse gas forcing of approximately 10-18%. The simplified approach presented here neglects many important processes that may amplify or mitigate C release from permafrost soils, but serves as a data-constrained estimate on the forced, large-scale permafrost C response to warming.


Asunto(s)
Carbono/química , Cambio Climático/estadística & datos numéricos , Ecosistema , Monitoreo del Ambiente/métodos , Modelos Estadísticos , Hielos Perennes/química , Carbono/análisis , Simulación por Computador , Bases de Datos Factuales , Retroalimentación , Congelación , Modelos Químicos
10.
Proc Biol Sci ; 280(1766): 20131336, 2013 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-23843394

RESUMEN

How plants respond to climatic perturbations, which are forecasted to increase in frequency and intensity, is difficult to predict because of the buffering effects of plasticity. Compensatory adjustments may maintain fecundity and recruitment, or delay negative changes that are inevitable but not immediately evident. We imposed a climate perturbation of warming and drought on a mixed-mating perennial violet, testing for adjustments in growth, reproduction and mortality. We observed several plasticity-based buffering responses, such that the climatic perturbation did not alter population structure. The most substantial reproductive adjustments, however, involved selfing, with a 45% increase in self-pollination by chasmogamous flowers, a 61% increase in the number of cleistogamous flowers that produced at least one fruit and an overall 15% increase in fruit production from selfed cleistogamous flowers. Reproductive assurance thus compensated for environmental change, including low pollinator visitation that occurred independently of our climate treatment. There was also no immediate evidence for inbreeding depression. Our work indicates that plants with vegetative and reproductive flexibility may not be immediately and negatively affected by a climatic perturbation. The stabilizing effects of these reproductive responses in the long term, however, may depend on the implications of significantly elevated levels of selfing.


Asunto(s)
Flores/fisiología , Viola/fisiología , Cambio Climático , Fertilidad , Flores/anatomía & histología , Polinización , Temperatura , Viola/anatomía & histología
11.
Nature ; 494(7435): 86-9, 2013 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-23389543

RESUMEN

Long-term and persistent human disturbances have simultaneously altered the stability and diversity of ecological systems, with disturbances directly reducing functional attributes such as invasion resistance, while eliminating the buffering effects of high species diversity. Theory predicts that this combination of environmental change and diversity loss increases the risk of abrupt and potentially irreversible ecosystem collapse, but long-term empirical evidence from natural systems is lacking. Here we demonstrate this relationship in a degraded but species-rich pyrogenic grassland in which the combined effects of fire suppression, invasion and trophic collapse have created a species-poor grassland that is highly productive, resilient to yearly climatic fluctuations, and resistant to invasion, but vulnerable to rapid collapse after the re-introduction of fire. We initially show how human disturbance has created a negative relationship between diversity and function, contrary to theoretical predictions. Fire prevention since the mid-nineteenth century is associated with the loss of plant species but it has stabilized high-yield annual production and invasion resistance, comparable to a managed high-yield low-diversity agricultural system. In managing for fire suppression, however, a hidden vulnerability to sudden environmental change emerges that is explained by the elimination of the buffering effects of high species diversity. With the re-introduction of fire, grasslands only persist in areas with remnant concentrations of native species, in which a range of rare and mostly functionally redundant plants proliferate after burning and prevent extensive invasion including a rapid conversion towards woodland. This research shows how biodiversity can be crucial for ecosystem stability despite appearing functionally insignificant beforehand, a relationship probably applicable to many ecosystems given the globally prevalent combination of intensive long-term land management and species loss.


Asunto(s)
Biodiversidad , Ecosistema , Actividades Humanas , Biomasa , Cambio Climático , Ecología/métodos , Incendios , Especies Introducidas , Poaceae/crecimiento & desarrollo , Dinámica Poblacional , Árboles/crecimiento & desarrollo
12.
Oecologia ; 170(4): 1123-32, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22669263

RESUMEN

The global expansion of species beyond their ancestral ranges can derive from mechanisms that are trait-based (e.g., post-establishment evolved differences compared to home populations) or circumstantial (e.g., propagule pressure, with no trait-based differences). These mechanisms can be difficult to distinguish following establishment, but each makes unique predictions regarding trait similarity between ancestral ('home') and introduced ('away') populations. Here, we tested for trait-based population differences across four continents for the globally distributed grass Dactylis glomerata, to assess the possible role of trait evolution in its worldwide expansion. We used a common-environment glasshouse experiment to quantify trait differences among home and away populations, and the potential relevance of these differences for competitive interactions. Few significant trait differences were found among continents, suggesting minimal change during global expansion. All populations were polyploids, with similar foliar carbon:nitrogen ratios (a proxy for defense), chlorophyll content, and biomass. Emergence time and growth rate favored home populations, resulting in their competitive superiority over away populations. Small but significant trait differences among away populations suggest different introductory histories or local adaptive responses following establishment. In summary, the worldwide distribution of this species appears to have arisen from its pre-adapted traits promoting growth, and its repeated introduction with cultivation and intense propagule pressure. Global expansion can thus occur without substantial shifts in growth, reproduction, or defense. Rather than focusing strictly on the invader, invasion success may also derive from the traits found (or lacking) in the recipient community and from environmental context including human disturbance.


Asunto(s)
Evolución Biológica , Dispersión de las Plantas , Poaceae/crecimiento & desarrollo , Biomasa , Clorofila , Ecosistema , Reproducción
13.
J Neurophysiol ; 86(6): 2678-89, 2001 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11731528

RESUMEN

In an overarm throw, as the hand opens and the ball rolls along the fingers, the ball exerts a back force on the fingers. Previous studies suggested that skilled throwers compensate for this back force by producing an appropriate finger flexor torque to oppose the back force, but it was unclear how this is controlled by the CNS. We investigated whether the increase in finger flexor torque is timed precisely to occur late in the throw as the fingers open or whether the increase occurs throughout the throw to anticipate the increase in hand acceleration. Recreational ball players threw balls of different weights and diameters at different speeds from both a sitting and standing position while arm joint rotations were recorded with the search-coil technique. Force transducers were taped to the distal and middle phalanges of the middle finger and subjects released the ball from this finger. Passive forces on the finger were also recorded in "fake" throws in which the ball was taped to the finger and subjects did not grip the ball. These skilled throwers correctly anticipated the magnitude of the back force from the ball on the finger because the mean amplitude of finger extension did not increase in throws made with a large range of increasing back forces. This was achieved by subjects gripping the ball during the backswing with a force proportional to ball weight and intended ball speed (acceleration) and progressively increasing the grip force throughout the backswing and forward throw. The magnitude of this grip force during the forward throw was not affected by ball texture. After ball release from the fingertip, the finger flexed in proportion to the peak force on the finger before ball release. It is concluded, in a skilled fast overarm throw where large, fast-changing forces on the fingers result from the sum of motions at all arm joints, that finger flexor torque is progressively increased throughout the throw in an anticipatory (predictive) fashion to counteract the progressively increasing back force from the ball.


Asunto(s)
Brazo/fisiología , Sistema Nervioso Central/fisiología , Dedos/fisiología , Fuerza de la Mano/fisiología , Destreza Motora/fisiología , Adulto , Brazo/inervación , Fenómenos Biomecánicos , Dedos/inervación , Humanos , Masculino , Persona de Mediana Edad
14.
Biomacromolecules ; 2(2): 450-5, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11749205

RESUMEN

The swelling of tomato pectin and isolated tomato pericarp cell wall material was investigated in aqueous media under different ionic conditions, pH, and external osmotic stress. Conditions were chosen to include those that would be encountered in vivo. Swelling in these systems was strongly influenced by the polyelectrolyte nature of the polymer and the extent of cross-linking with divalent counterions.


Asunto(s)
Pared Celular/química , Pectinas/química , Proteínas de Plantas/química , Solanum lycopersicum/citología , Frutas/citología , Concentración de Iones de Hidrógeno , Presión Osmótica , Proteínas de Plantas/aislamiento & purificación , Cloruro de Potasio/química
15.
Carbohydr Res ; 335(2): 115-26, 2001 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-11567642

RESUMEN

The effect of basic peptides on the gelation of a pectin from the cell wall of tomato was examined through the determination of gel stiffness, and swelling behaviour of the gel in water. Poly-L-lysine, poly-L-arginine, and a synthetic peptide, designed to mimic a sequence of basic amino acids found in a plant cell wall extensin, act as crosslinking agents. Circular dichroism studies on the interaction of synthetic extensin peptides with sodium polygalacturonate demonstrated that a conformational change was induced as a result of their complexation. In addition to their effect as crosslinking agents, the polycationic peptides reduced the swelling of the pectin network in water.


Asunto(s)
Pared Celular/química , Glicoproteínas/química , Pectinas/química , Péptidos/química , Proteínas de Plantas/química , Secuencia de Aminoácidos , Aminoácidos Básicos/química , Reactivos de Enlaces Cruzados/química , Daucus carota , Geles , Hidroxiprolina/química , Solanum lycopersicum , Mecánica , Datos de Secuencia Molecular , Polilisina/química
16.
Carbohydr Res ; 333(1): 47-58, 2001 Jun 22.
Artículo en Inglés | MEDLINE | ID: mdl-11423110

RESUMEN

A specific, chemical degradation of the methyl esterified galacturonic acid residues of pectins is described. These residues are converted, with hydroxylamine, to hydroxamic acids, and then, with a carbodiimide, to isoureas; the latter undergo a Lossen rearrangement on alkaline hydrolysis. The isocyanates formed are hydrolysed to 5-aminoarabinopyranose derivatives, which spontaneously ring open to give 1,5-dialdehydes. The latter are reduced, in situ, to avoid peeling reactions, with sodium borohydride to give substituted arabitol residues. Thus, overall, partially esterified pectins are specifically cleaved to generate a series of oligogalacturonic acids bearing an arabitol residue as aglycone. Analysis of oligomers so generated discloses the pattern of contiguous nonesterification in a variety of pectins of differing degrees of esterification. Other potential applications are described.


Asunto(s)
Pectinas/química , Esterificación , Etildimetilaminopropil Carbodiimida , Ácidos Hexurónicos/química , Ácidos Hidroxámicos/química , Hidroxilamina , Espectroscopía de Resonancia Magnética , Oxidación-Reducción , Espectrometría de Masa por Ionización de Electrospray
17.
Carbohydr Res ; 331(3): 337-42, 2001 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-11383904

RESUMEN

Atomic force microscopy (AFM) has been used to investigate the nature of the long branches attached to pectin which were described in a previous report [Round, A. N.; MacDougall, A. J.; Ring, S. G.; Morris, V. J. Carbohydr. Res. 1997, 303, 251-253]. Analysis of the AFM images and comparison with neutral sugar and linkage analyses of the two pectin fractions suggest that the distribution and total amount of branches observed do not correspond with the pattern of neutral sugar distribution. It is thus postulated that the long chains consist of polygalacturonic acid, attached via an as yet undetermined linkage to the pectin backbone, with the neutral sugars present as short, undetected branches. This explanation would have important implications for the nature of 'in situ' pectin networks within plant cell walls and models of gelation in commercial extracted pectin, and the existence of significant branching will markedly influence the viscosity of extracted pectins.


Asunto(s)
Carbohidratos/química , Microscopía de Fuerza Atómica , Pectinas/química , Estructura Molecular
18.
Can J Neurol Sci ; 28(1): 61-5, 2001 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-11252298

RESUMEN

BACKGROUND: Glioblastoma Multiforme (GBM) is the most common and malignant brain tumor in adults. The median survival in patients harboring this neoplasm is 12 months irrespective of any form of therapy. Health care costs of illnesses with high mortality rates, such as GBM, are of particular interest in times of constrained health care resources. No information regarding costs for the treatment of patients with GBM is available in Canada. The aim of this study was to conduct an analysis of the costs of treatment of GBM in Nova Scotia. METHODS: Patients with histologically proven GBM during a three year period (1996-1998) in Nova Scotia were included in the study. Analysis was based on hospital costs supplemented by data on additional medical services received following discharge for the primary intervention. RESULTS: The mean cost of medical care per patient from the time of diagnosis to death was $17,149. The highest costs were related to hospitalization with ward costs alone accounting for 48% of all costs. Radiotherapy costs were 25%, surgery costs were 16% and chemotherapy costs were 7% of all costs. Costs for diagnostic procedures were 6% of the total costs. CONCLUSION: Our data reflect the costs and practice pattern in the treatment of GBM in Nova Scotia and may be of value as an initial attempt to analyze costs of treatment of GBM in Canada.


Asunto(s)
Neoplasias Encefálicas/economía , Neoplasias Encefálicas/terapia , Glioblastoma/economía , Glioblastoma/terapia , Adulto , Anciano , Neoplasias Encefálicas/cirugía , Terapia Combinada/economía , Femenino , Glioblastoma/cirugía , Humanos , Masculino , Persona de Mediana Edad , Procedimientos Neuroquirúrgicos/economía , Nueva Escocia , Análisis de Supervivencia
19.
J Immunol ; 166(4): 2296-302, 2001 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-11160285

RESUMEN

Gammadelta T cells show preferential homing that is characterized by biased TCR repertoire at different anatomical locations. The processes that regulate this compartmentalization are largely unknown. A model that allows repeated multiple sample procurement under different conditions and enables with relatively straightforward extrapolation to a human situation will facilitate our understanding. The peripheral blood Vgamma2 T cell population is the best-characterized human gammadelta T cell subset. To determine its diversity at multiple immunocompartments matching blood, colon, and vagina samples from rhesus macaques were investigated. Four joining segments used in Vgamma2-Jgamma transcripts were identified, including one segment with no human counterpart. Like in humans, the rhesus peripheral blood Vgamma2 TCR repertoire was limited and contained common sequences that were shared by genetically heterogeneous animals. Furthermore, this subset comprised several phylogenetically conserved Vgamma2 complementarity-determining region 3 (CDR3) motifs between rhesus and humans. Common sequences were also found within the colon and vagina of the same animal, and within the peripheral blood and intestine of different unrelated animals. These results validate rhesus macaques as a useful model for gammadelta TCR repertoire and homing studies. Moreover, they provide evidence that the concept of limited but overlapping Vgamma TCR repertoire between unrelated individuals can be extended including the mucosa of the digestive and reproductive tract.


Asunto(s)
Especificidad de Órganos/genética , Especificidad de Órganos/inmunología , Receptores de Antígenos de Linfocitos T gamma-delta/biosíntesis , Receptores de Antígenos de Linfocitos T gamma-delta/genética , Secuencias de Aminoácidos/genética , Secuencias de Aminoácidos/inmunología , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Colon Sigmoide/inmunología , Colon Sigmoide/metabolismo , Femenino , Genes Codificadores de la Cadena gamma de los Receptores de Linfocito T , Humanos , Mucosa Intestinal/inmunología , Mucosa Intestinal/metabolismo , Macaca mulatta , Masculino , Datos de Secuencia Molecular , Receptores de Antígenos de Linfocitos T gamma-delta/sangre , Alineación de Secuencia , Homología de Secuencia de Aminoácido , Homología de Secuencia de Ácido Nucleico , Transcripción Genética/inmunología , Vagina/inmunología , Vagina/metabolismo
20.
Carbohydr Res ; 328(2): 235-9, 2000 Sep 08.
Artículo en Inglés | MEDLINE | ID: mdl-11028791

RESUMEN

Oligogalacturonates were produced by the limited enzymic hydrolysis of polygalacturonic acid and purified by ion-exchange chromatography. The fractions obtained were of limited polydispersity, determined by analytical ion-exchange chromatography. Oligomers with an average degree of polymerization of 10-15 were readily crystallized from aqueous salt solutions at neutral pH as single crystals. Crystal morphology of the salts examined, Na+, K+ and Ca2+ were characteristic of the salt. The wide-angle X-ray diffraction patterns obtained for the sodium salt were consistent with published fibre diffraction data of this salt form.


Asunto(s)
Ácidos Hexurónicos/química , Cromatografía por Intercambio Iónico , Cristalografía , Hidrólisis , Microscopía Electrónica , Oligosacáridos/química , Pectinas/química , Sales (Química)/farmacología , Difracción de Rayos X
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