960 resultados para potassium 42


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The objective of this work was to investigate possible maternal effects on potassium content of common bean seeds, as well as to estimate the heritability and selection gains in early hybrid generations for this character and to evaluate the efficiency of genetic selection to improve the nutritional quality of common bean (Phaseolus vulgaris). Crosses with four cultivars from the Mesoamerican gene pool yielded the reciprocal F1 and F2 generations and the backcrossed populations (BCP1 and BCP2). The potassium content of the progenies was measured via nitric‑perchloric digestion and flame photometry. The potassium content in the tested progenies varied from 6.0 to 14.9 g kg-1 dry matter, and no significant maternal effect was observed. The narrow-sense heritability ranged from low (33.26%) to intermediate (43.05%). Partial dominance was observed for low potassium content in the seeds. No increase in potassium content was obtained through selection. Breeding common bean plants for increasing potassium content in seeds may be difficult because the local environment strongly influences the character.

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The objective of this work was to adapt the application of electrolytic conductivity and potassium leaching tests to assess the viability of cryopreserved embryos of 'Anão Verde do Brasil de Jiqui' (AVeJBr) coconut. The zygotic embryos were excised, sterilized and subjected to four cryoprotectant treatments combined with three incubation times (12, 16 and 20 hours), totaling 12 treatments. The pre-treatment of mature zygotic embryos of AVeJBr coconut using a cryoprotectant with 1.75 mol L-1 of sucrose + 15% glycerol for 12 and 16 hours promoted lower embryo humidity and increased viability in electrolytic conductivity and potassium leaching tests. Samples with ten embryos are sufficient for electrolytic conductivity analysis in cryopreserved or non-cryopreserved AVeJBr coconut zygotic embryos. The 4 to 8 hour imbibition period of the embryos is promising for the electrolytic conductivity analysis of non-cryopreserved mature zygotic embryos of AVeJBr coconut.

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The Iowa Influenza Surveillance Network (IISN) was established in 2004, though surveillance has been conducted at the Iowa Department of Public Health. Schools and long-term care facilities report data weekly into a Web-based reporting system. Schools report the number of students absent due to illness and the total enrolled. Long-term care facilities report cases of influenza and vaccination status of each case. Both passively report outbreaks of illness, including influenza, to IDPH.

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Astrocytes fulfill a central role in regulating K+ and glutamate, both released by neurons into the extracellular space during activity. Glial glutamate uptake is a secondary active process that involves the influx of three Na+ ions and one proton and the efflux of one K+ ion. Thus, intracellular K+ concentration ([K+]i) is potentially influenced both by extracellular K+ concentration ([K+]o) fluctuations and glutamate transport in astrocytes. We evaluated the impact of these K+ ion movements on [K+]i in primary mouse astrocytes by microspectrofluorimetry. We established a new noninvasive and reliable approach to monitor and quantify [K+]i using the recently developed K+ sensitive fluorescent indicator Asante Potassium Green-1 (APG-1). An in situ calibration procedure enabled us to estimate the resting [K+]i at 133±1 mM. We first investigated the dependency of [K+]i levels on [K+]o. We found that [K+]i followed [K+]o changes nearly proportionally in the range 3-10 mM, which is consistent with previously reported microelectrode measurements of intracellular K+ concentration changes in astrocytes. We then found that glutamate superfusion caused a reversible drop of [K+]i that depended on the glutamate concentration with an apparent EC50 of 11.1±1.4 µM, corresponding to the affinity of astrocyte glutamate transporters. The amplitude of the [K+]i drop was found to be 2.3±0.1 mM for 200 µM glutamate applications. Overall, this study shows that the fluorescent K+ indicator APG-1 is a powerful new tool for addressing important questions regarding fine [K+]i regulation with excellent spatial resolution.

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Scand J Clin Lab Invest. 2007 Aug 1;:1-11 [Epub ahead of print]

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BACKGROUND: The limitations of the medical management of symptomatic intracranial arterial stenosis encourage the development of new therapeutic strategies such as intracranial stenting. OBJECTIVE: To report and analyze the results of a series of 42 patients treated with 3 different endovascular techniques: isolated angioplasty, balloon-expandable coronary stents, and the Wingspan self-expandable intracranial stent system. METHODS: Forty-two patients presenting with symptomatic intracranial arterial stenosis were treated with one of these techniques. Computed tomography angiography was performed 6 months after the procedure, and the clinical neurological statuses were categorized using the modified Rankin Scale and the National Institutes of Health Stroke Scale. RESULTS: A total of 42 lesions were treated: 9 with isolated angioplasty, 14 with balloon-expandable coronary stents, and 19 with Wingspan self-expandable intracranial stents. The mean patient age was 62.9 years, and the mean arterial diameter stenosis was 73.9%. Technical success was achieved in 97.6% of the patients. The overall incidence of procedural complications was 21.4%, and the postoperative permanent morbidity/mortality rate was 7.1%. There were 3 cases of in-stent thrombosis (1 fatal) and 5 cases of asymptomatic restenosis (11.9%), 3 in the isolated angioplasty group and 2 in the Wingspan self-expandable intracranial stent group (mean follow-up 20.4 months). The rate of restenosis was higher in the angioplasty group (33%) than in the coronary (0%) and Wingspan stent (10.5%) groups. CONCLUSION: Endovascular treatment of symptomatic intracranial stenosis has significant overall morbidity and mortality rates. Nevertheless, the very critical natural history of severe refractory lesions and the relatively favorable postoperative evolution suggest that it should be considered the first alternative strategy in cases in which medical therapy has failed.

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BACKGROUND: Very preterm (VP) infants are at greater risk for cognitive difficulties that may persist during school-age, adolescence and adulthood. Behavioral assessments report either effortful control (part of executive functions) or emotional reactivity/regulation impairments. AIMS: The aim of this study is to examine whether emotional recognition, reactivity, and regulation, as well as effortful control abilities are impaired in very preterm children at 42 months of age, compared with their full-term peers, and to what extent emotional and effortful control difficulties are linked. STUDY DESIGN: Children born very preterm (VP; < 29 weeks gestational age, n=41) and full-term (FT) aged-matched children (n=47) participated in a series of specific neuropsychological tests assessing their level of emotional understanding, reactivity and regulation, as well as their attentional and effortful control abilities. RESULTS: VP children exhibited higher scores of frustration and fear, and were less accurate in naming facial expressions of emotions than their aged-matched peers. However, VP children and FT children equally performed when asked to choose emotional facial expression in social context, and when we assessed their selective attention skills. VP performed significantly lower than full terms on two tasks of inhibition when correcting for verbal skills. Moreover, significant correlations between cognitive capacities (effortful control) and emotional abilities were evidenced. CONCLUSIONS: Compared to their FT peers, 42 month-olds who were born very preterm are at higher risk of exhibiting specific emotional and effortful control difficulties. The results suggest that these difficulties are linked. Ongoing behavioral and emotional impairments starting at an early age in preterms highlight the need for early interventions based on a better understanding of the relationship between emotional and cognitive difficulties.

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Mutations in α, β, or γ subunits of the epithelial sodium channel (ENaC) can downregulate ENaC activity and cause a severe salt-losing syndrome with hyperkalemia and metabolic acidosis, designated pseudohypoaldosteronism type 1 in humans. In contrast, mice with selective inactivation of αENaC in the collecting duct (CD) maintain sodium and potassium balance, suggesting that the late distal convoluted tubule (DCT2) and/or the connecting tubule (CNT) participates in sodium homeostasis. To investigate the relative importance of ENaC-mediated sodium absorption in the CNT, we used Cre-lox technology to generate mice lacking αENaC in the aquaporin 2-expressing CNT and CD. Western blot analysis of microdissected cortical CD (CCD) and CNT revealed absence of αENaC in the CCD and weak αENaC expression in the CNT. These mice exhibited a significantly higher urinary sodium excretion, a lower urine osmolality, and an increased urine volume compared with control mice. Furthermore, serum sodium was lower and potassium levels were higher in the genetically modified mice. With dietary sodium restriction, these mice experienced significant weight loss, increased urinary sodium excretion, and hyperkalemia. Plasma aldosterone levels were significantly elevated under both standard and sodium-restricted diets. In summary, αENaC expression within the CNT/CD is crucial for sodium and potassium homeostasis and causes signs and symptoms of pseudohypoaldosteronism type 1 if missing.

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Estacas apicais herbáceas de ramos plagiotrópicos do cacaueiro (clones CEPEC 42, TSH 516 e TSH 1188) foram tratadas com 0 e 6.000 mg.kg-1 do ácido indolbutírico (AIB) e estaqueadas em tubetes de 288 cm³ contendo como substrato uma mistura de Plantmax® e fibra de coco triturada (1:1), enriquecido com Osmocote® (19-06-20) e PG mix® (14-16-18). Os tubetes foram acondicionados em bandejas e estas foram mantidas em câmaras de nebulização. Na avaliação, realizada aos 78 dias após o estaqueamento, verificou-se que, independentemente da aplicação de AIB, as estacas dos clones avaliados apresentaram índices de enraizamento superiores a 87%, mas o tratamento das estacas com AIB aumentou os índices de sobrevivência e de estacas enraizadas de todos os clones, número de raízes (clones TSH 516 e TSH 1188), matéria seca de raízes (Clones CEPEC 42 e TSH 516) e matéria seca da parte aérea (Clones TSH 566 e TSH 1188).

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Haloesterification of diverse diols with various carboxylic acids was achieved using potassium halides (KX) as the only halide source in ionic liquids. The best yield was obtained in [BMIM][PF6] when 1,2-octanediol, palmitic acid and KBr were used. This yield was 85% and the regioisomer with the bromine in primary position was present in a 75:25 ratio. The regioisomeric ratio could be improved using either KCl or some phenylcarboxylic acids. [BMIM][PF6] acts as both reaction media and catalyst of the reaction. To the best of our knowledge, this type of combined reaction using an ionic liquid is unprecedented. The other solvents tested did not lead either to the same yield or to the same regioisomeric ratio.

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Aldosterone stimulates transepithelial Na+ transport in the toad bladder, and thyroid hormone antagonizes this mineralocorticoid action. In the present study, we assessed the influence of these two hormones on the biosynthesis of (Na+,K+)ATPase, the major driving force of Na+ transport. Rates of enzyme synthesis were estimated by immunoprecipitation with monospecific alpha (96,000 daltons) and beta (60,000 daltons) subunit antibodies. After a 30-min pulse of intact tissue with [35S]methionine, the anti-alpha-serum recognized the 96,000-dalton alpha subunit and the anti-beta-serum, a 42,000-dalton protein, in total cell extracts. The biosynthesis rates of both these proteins were increased 2.8- and 2.4-fold respectively, over controls by 80 nM aldosterone after 18 h of hormone treatment. The hormonal effect was not apparent up to 3 h of incubation and was dose dependent between 0.2 and 20 nM aldosterone. The hormonal induction was antagonized by spironolactone (500-fold excess) but not by amiloride. The action of aldosterone thus seems to be a receptor-mediated process and a primary event independent of the Na+ permeability of the apical membrane. Thyroid hormone, on the other hand, had no effect on either basal or aldosterone-stimulated synthesis rates of both enzyme proteins. The results demonstrate a direct effect of aldosterone on gene expression of the (Na+,K+)-ATPase. Ultimately, this phenomenon could be linked to the late mineralocorticoid action of this hormone. On the other hand, thyroid hormone, in contrast to the situation in mammals, does not stimulate de novo enzyme synthesis in amphibia. Neither can the antimineralocorticoid action of thyroid hormone in the toad bladder be explained by an inhibition of the (Na+,K+)-ATPase synthesis.

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Yield and physical and chemical characteristics of 'Paluma' guava fruit were evaluated as a function of the harvest at different maturity stages, under influence of nitrogen and potassium fertilization, in Petrolina, State of Pernambuco, Brazil. Fertilizer rates were 67 kg N + 33 kg K2O, 133 kg N + 67 kg K2O, 200 kg N + 100 kg K2O and 267 kg N + 133 kg K2O per hectare. Fruits were evaluated at maturity stages 2, 3, 4 and 5, established according to peel color. Higher doses of N and K induced higher yields. Nevertheless, fertilization with 200 kg of N + 100 kg of K per hectare improved fruit quality, delaying ascorbic acid breakdown and conserving pulp firmness. Main changes took place at maturity stages 4 and 5, when the fruit should present ideal conditions for consumption, namely the increase on soluble solids and soluble sugars content.

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BACKGROUND: In 2011, a patient was admitted to our hospital with acute schistosomiasis after having returned from Madagascar and having bathed at the Lily waterfalls. On the basis of this patient's indication, infection was suspected in 41 other subjects. This study investigated (1) the knowledge of the travelers about the risks of schistosomiasis and their related behavior to evaluate the appropriateness of prevention messages and (2) the diagnostic workup of symptomatic travelers by general practitioners to evaluate medical care of travelers with a history of freshwater exposure in tropical areas. METHODS: A questionnaire was sent to the 42 travelers with potential exposure to schistosomiasis. It focused on pre-travel knowledge of the disease, bathing conditions, clinical presentation, first suspected diagnosis, and treatment. RESULTS: Of the 42 questionnaires, 40 (95%) were returned, among which 37 travelers (92%) reported an exposure to freshwater, and 18 (45%) were aware of the risk of schistosomiasis. Among these latter subjects, 16 (89%) still reported an exposure to freshwater. Serology was positive in 28 (78%) of 36 exposed subjects at least 3 months after exposure. Of the 28 infected travelers, 23 (82%) exhibited symptoms and 16 (70%) consulted their general practitioner before the information about the outbreak had spread, but none of these patients had a serology for schistosomiasis done during the first consultation. CONCLUSIONS: The usual prevention message of avoiding freshwater contact when traveling in tropical regions had no impact on the behavior of these travelers, who still went swimming at the Lily waterfalls. This prevention message should, therefore, be either modified or abandoned. The clinical presentation of acute schistosomiasis is often misleading. General practitioners should at least request an eosinophil count, when confronted with a returning traveler with fever. If eosinophilia is detected, it should prompt the search for a parasitic disease.