963 resultados para vegetative axis
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Canola (Brassica napus L.) and sunflower (Helianthus annuus L.), two important oilseed crops, are sensitive to low boron (B) supply. Symptoms of B deficiency are often more severe during the reproductive stage, but it is not known if this is due to a decreased external B supply with time or an increased sensitivity to low B during this stage. Canola and sunflower were grown for 75 days after transplanting (DAT) in two solution culture experiments using Amberlite (IRA-743) B-specific resin to maintain constant B concentration in solution over the range 0.6 - 53 muM. Initially, the vegetative growth of both crops was good in all treatments. With the onset of the reproductive stage, however, severe B deficiency symptoms developed and growth of canola and sunflower was reduced with less than or equal to 0.9 and less than or equal to 0.7 muM B, respectively. At these concentrations, reproductive parts failed to develop. The critical B concentration (i.e. 90% of maximum shoot dry matter yield) in the youngest opened leaf was 18 mg kg(-1) in canola and 25 mg kg(-1) in sunflower at 75 DAT. The results of this study indicate that the reproductive stage of these two oilseed crops is more sensitive than the vegetative stage to low B supply.
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The polyphase evolution of the Serido Belt (NE-Brazil) includes D, crust formation at 2.3-2.1 Ga, D-2 thrust tectonics at 1.9 Ga and crustal reworking by D-3 strike-slip shear zones at 600 Ma. Microstructural investigations within mylonites associated with D-2 and D-3 events were used to constrain the tectono-thermal evolution of the belt. D-2 shear zones commenced at deeper crustal levels and high amphibolite facies conditions (600-650 degreesC) through grain boundary migration, subgrain rotation and operation of quartz Q-prism slip. Continued shearing and exhumation of the terrain forced the re-equilibration of high-T fabrics and the switching of slip systems from (c)-prism to positive and negative (a)-rhombs. During D-3, enhancement of ductility by dissipation of heat that came from syn-D-3 granites developed wide belts of amphibolite facies mylonites. Continued shearing, uplift and cooling of the region induced D-3 shear zones to act in ductile-brittle regimes, marked by fracturing and development of thinner belts of greenschist facies mylonites. During this event, switching from (a)-prism to a basal slip indicates a thermal path from 600 to 350 degreesC. Therefore, microstructures and quartz c-axis fabrics in polydeformed rocks from the Serido Belt preserve the record of two major events, which includes contrasting deformation mechanisms and thermal paths. (C) 2003 Elsevier Ltd. All rights reserved.
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Abnormalities of calcium and vitamin D metabolism in cystic fibrosis (CF) are well documented. We tested the hypothesis that alterations in calcium metabolism are related to vitamin D deficiency, and that bone resorption is increased relative to accretion in patients with CF. Calcitropic hormones, electrolytes, osteocalcin (OC) and bone alkaline phosphatase (BAP), (markers of bone mineralisation), urinary deoxypyridinoline [total (t) Dpd, a marker of bone resorption] and lumbar spine bone mineral density (LS BMD), expressed as a z-score, were measured in 149 (81 M) CF and 141 (61 M) control children aged 5.3-10.99 years, adolescents aged 11-17.99 years and adults aged 18-55.9 years. Data were analysed by multiple regression to adjust for age. In patients, FEV1% predicted and CRP (as disease severity markers), genotype and pancreatic status (PS) were recorded. The distribution of PTH differed between groups (P
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The Iberian viticultural regions are convened according to the Denomination of Origin (DO) and present different climates, soils, topography and management practices. All these elements influence the vegetative growth of different varieties throughout the peninsula, and are tied to grape quality and wine type. In the current study, an integrated analysis of climate, soil, topography and vegetative growth was performed for the Iberian DO regions, using state-of-the-art datasets. For climatic assessment, a categorized index, accounting for phenological/thermal development, water availability and grape ripening conditions was computed. Soil textural classes were established to distinguish soil types. Elevation and aspect (orientation) were also taken into account, as the leading topographic elements. A spectral vegetation index was used to assess grapevine vegetative growth and an integrated analysis of all variables was performed. The results showed that the integrated climate-soil-topography influence on vine performance is evident. Most Iberian vineyards are grown in temperate dry climates with loamy soils, presenting low vegetative growth. Vineyards in temperate humid conditions tend to show higher vegetative growth. Conversely, in cooler/warmer climates, lower vigour vineyards prevail and other factors, such as soil type and precipitation acquire more important roles in driving vigour. Vines in prevailing loamy soils are grown over a wide climatic diversity, suggesting that precipitation is the primary factor influencing vigour. The present assessment of terroir characteristics allows direct comparison among wine regions and may have great value to viticulturists, particularly under a changing climate.
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Dissertação para obtenção do Grau de Mestre em Genética Molecular e Biomedicina
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Density-dependent responses are an important component of the organism life-history, and the resource allocation theory is a central concept to the life-history theory. When resource allocation varies due to environmental changes, a plant may change its morphology or physiology to cope with the new conditions, a process known as phenotypic plasticity. Our study aimed to evaluate how plant density affects Eichhornia crassipes allocation patterns. A total of 214 individuals in high and low density were collected. The density effect was observed in all plant traits examined including biomass accumulation. All traits of E. crassipes demonstrated higher values in high density conditions, except for biomass of leaves. Density exhibited a high influence on vegetative traits of E. crassipes, but did not influence allocation pattern, since a trade-off among the vegetative traits was not found. The morphological plasticity and the absence of trade-offs were discussed as strategies to overcome neighbor plants in competition situations. In high density conditions, there were clear changes in the morphology of the plants which probably allows for their survival in a highly competitive environment.
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RATIONALE: A dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis is a well-documented neurobiological finding in major depression. Moreover, clinically effective therapy with antidepressant drugs may normalize the HPA axis activity. OBJECTIVE: The aim of this study was to test whether citalopram (R/S-CIT) affects the function of the HPA axis in patients with major depression (DSM IV). METHODS: Twenty depressed patients (11 women and 9 men) were challenged with a combined dexamethasone (DEX) suppression and corticotropin-releasing hormone (CRH) stimulation test (DEX/CRH test) following a placebo week and after 2, 4, and 16 weeks of 40 mg/day R/S-CIT treatment. RESULTS: The results show a time-dependent reduction of adrenocorticotrophic hormone (ACTH) and cortisol response during the DEX/CRH test both in treatment responders and nonresponders within 16 weeks. There was a significant relationship between post-DEX baseline cortisol levels (measured before administration of CRH) and severity of depression at pretreatment baseline. Multiple linear regression analyses were performed to identify the impact of psychopathology and hormonal stress responsiveness and R/S-CIT concentrations in plasma and cerebrospinal fluid (CSF). The magnitude of decrease in cortisol responsivity from pretreatment baseline to week 4 on drug [delta-area under the curve (AUC) cortisol] was a significant predictor (p<0.0001) of the degree of symptom improvement following 16 weeks on drug (i.e., decrease in HAM-D21 total score). The model demonstrated that the interaction of CSF S-CIT concentrations and clinical improvement was the most powerful predictor of AUC cortisol responsiveness. CONCLUSION: The present study shows that decreased AUC cortisol was highly associated with S-CIT concentrations in plasma and CSF. Therefore, our data suggest that the CSF or plasma S-CIT concentrations rather than the R/S-CIT dose should be considered as an indicator of the selective serotonergic reuptake inhibitors (SSRIs) effect on HPA axis responsiveness as measured by AUC cortisol response.
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Background Decisions on limiting life-sustaining treatment for patients in the vegetative state (VS) are emotionally and morally challenging. In Germany, doctors have to discuss, together with the legal surrogate (often a family member), whether the proposed treatment is in accordance with the patient's will. However, it is unknown whether family members of the patient in the VS actually base their decisions on the patient's wishes. Objective To examine the role of advance directives, orally expressed wishes, or the presumed will of patients in a VS for family caregivers' decisions on life-sustaining treatment. Methods and sample A qualitative interview study with 14 next of kin of patients in a VS in a long-term care setting was conducted; 13 participants were the patient's legal surrogates. Interviews were analysed according to qualitative content analysis. Results The majority of family caregivers said that they were aware of aforementioned wishes of the patient that could be applied to the VS condition, but did not base their decisions primarily on these wishes. They gave three reasons for this: (a) the expectation of clinical improvement, (b) the caregivers' definition of life-sustaining treatments and (c) the moral obligation not to harm the patient. If the patient's wishes were not known or not revealed, the caregivers interpreted a will to live into the patient's survival and non-verbal behaviour. Conclusions Whether or not prior treatment wishes of patients in a VS are respected depends on their applicability, and also on the medical assumptions and moral attitudes of the surrogates. We recommend repeated communication, support for the caregivers and advance care planning.
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The STEP HIV vaccine trial, which evaluated a replication-defective adenovirus type 5 (Ad5) vector vaccine, was recently stopped. The reasons for this included lack of efficacy of the vaccine and a twofold increase in the incidence of HIV acquisition among vaccinated recipients with increased Ad5-neutralizing antibody titers compared with placebo recipients. To model the events that might be occurring in vivo, the effect on dendritic cells (DCs) of Ad5 vector alone or treated with neutralizing antiserum (Ad5 immune complexes [IC]) was compared. Ad5 IC induced more notable DC maturation, as indicated by increased CD86 expression, decreased endocytosis, and production of tumor necrosis factor and type I interferons. We found that DC stimulation by Ad5 IC was mediated by the Fcgamma receptor IIa and Toll-like receptor 9 interactions. DCs treated with Ad5 IC also induced significantly higher stimulation of Ad5-specific CD8 T cells equipped with cytolytic machinery. In contrast to Ad5 vectors alone, Ad5 IC caused significantly enhanced HIV infection in DC-T cell cocultures. The present results indicate that Ad5 IC activates a DC-T cell axis that, together with the possible persistence of the Ad5 vaccine in seropositive individuals, may set up a permissive environment for HIV-1 infection, which could account for the increased acquisition of HIV-1 infection among Ad5 seropositive vaccine recipients.
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The aim of this study was to evaluate the effect of ovariectomy on the acute-phase response of inflammatory stress. Ex vivo adrenocortical, peripheral mononuclear cell (PMNC) and adipocyte activities were studied in intact and ovariectomized mice. Endotoxemia was mimicked by intraperitoneal administration of bacterial lipopolysaccharide (LPS; 25 mg per mouse) to sham-operated and 21-day ovariectomized mice. Circulating corticosterone, tumor necrosis factor-alpha (TNFalpha) and leptin concentrations were monitored before and 30-120 min after the administration of LPS. Additionally, in vitro experiments were performed with isolated corticoadrenal cells, PMNCs and omental adipocytes from sham-operated and ovariectomized mice incubated with specific secretagogues. The results indicate that while ovariectomy enhanced TNFalpha secretion after in vivo administration of LPS, it reduced corticoadrenal response and abrogated LPS-elicited leptin secretion into the circulation. While the corticoadrenal sensitivity to ACTH stimulation was reduced by ovariectomy, the LPS-induced PMNC response was not affected. Exogenous leptin enhanced baseline PMNC function regardless of surgery. Finally, ovariectomy drastically reduced in vitro adipocyte functionality. Our data support the notion that ovariectomy modified neuroendocrine-immune-adipocyte axis function and strongly suggest that ovarian activity could play a pivotal role in the development of an adequate immune defense mechanism after injury.
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Estrogens and progesterones are major drivers of breast development but also promote carcinogenesis in this organ. Yet, their respective roles and the mechanisms underlying their action in the human breast are unclear. Receptor activator of nuclear factor κB ligand (RANKL) has been identified as a pivotal paracrine mediator of progesterone function in mouse mammary gland development and mammary carcinogenesis. Whether the factor has the same role in humans is of clinical interest because an inhibitor for RANKL, denosumab, is already used for the treatment of bone disease and might benefit breast cancer patients. We show that progesterone receptor (PR) signaling failed to induce RANKL in PR(+) breast cancer cell lines and in dissociated, cultured breast epithelial cells. In clinical specimens from healthy donors and intact breast tissue microstructures, hormone response was maintained and RANKL expression was under progesterone control, which increased RNA stability. RANKL was sufficient to trigger cell proliferation and was required for progesterone-induced proliferation. The findings were validated in vivo where RANKL protein expression in the breast epithelium correlated with serum progesterone levels and the protein was expressed in a subset of luminal cells that express PR. Thus, important hormonal control mechanisms are conserved across species, making RANKL a potential target in breast cancer treatment and prevention.
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Purpose: To assess the clinical outcome of patients who were subjected to long-axis sacroplasty as first line treatment for sacral insufficiency fractures. Methods and materials: Nineteen patients with unilateral (n = 3) or bilateral (n = 16) sacral fractures were involved. Under local anaesthesia, each patient was subjected to CT guided sacroplasty using the long-axis approach through a single entry point. An average of 6 ml of PMMA was delivered along the path of each sacral fracture. For each individual patient, the VAS pain score before sacroplasty and at 1, 4, 24, and 48 weeks after the procedure was obtained. Furthermore, the use of analgesics (narcotic/non-narcotic) along with the evolution of post interventional patient mobility before and after sacroplasty was also recorded. Results: The mean pre-procedure VAS score was 8 ± 1.9. This has rapidly declined in the first week after the procedure (mean 4 ± 1.5) followed by gradual decrease along the rest of follow-up period at 4 weeks (mean 3 ± 1.2), 24 weeks (mean 2 ± 1.3), and 48 weeks (mean 1.3 ± 1.4), respectively. Eleven (58%) patients were under narcotic analgesia before sacroplasty, whereas, 8 (42%) patients were using non-narcotics. Corresponding values after the procedure were 2/19 (10%) (narcotic) and 10/19 53% (non-narcotic). Seven (37%) patients did not address post-procedure analgesic use. The evolution of post interventional mobility was favourable in the study group since they revealed a significant improvement in their mobility point scale. Conclusion: Long-axis percutaneous sacroplasty is a suitable minimally invasive treatment option for patients who present with sacral insufficiency fractures. Future studies with larger patient number are warranted to grasp any potential limitations of this therapeutic approach.