Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 4.298
Filtrar
1.
PLoS One ; 15(12): e0242878, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33332413

RESUMO

BACKGROUND: A powerful risk model allows clinicians, at the bedside, to ensure the early identification of and decision-making for patients showing signs of developing physiological instability during treatment. The aim of this study was to enhance the identification of patients at risk for deterioration through an accurate model using electrolyte, metabolite, and acid-base parameters near the end of patients' intensive care unit (ICU) stays. METHODS: This retrospective study included 5157 adult patients during the last 72 hours of their ICU stays. The patients from the MIMIC-III database who had serum lactate, pH, bicarbonate, potassium, calcium, glucose, chloride, and sodium values available, along with the times at which those data were recorded, were selected. Survivor data from the last 24 hours before discharge and four sets of nonsurvivor data from 48-72, 24-48, 8-24, and 0-8 hours before death were analyzed. Deep learning (DL), random forest (RF) and generalized linear model (GLM) analyses were applied for model construction and compared in terms of performance according to the area under the receiver operating characteristic curve (AUC). A DL backcasting approach was used to assess predictors of death vs. discharge up to 72 hours in advance. RESULTS: The DL, RF and GLM models achieved the highest performance for nonsurvivors 0-8 hours before death versus survivors compared with nonsurvivors 8-24, 24-48 and 48-72 hours before death versus survivors. The DL assessment outperformed the RF and GLM assessments and achieved discrimination, with an AUC of 0.982, specificity of 0.947, and sensitivity of 0.935. The DL backcasting approach achieved discrimination with an AUC of 0.898 compared with the DL native model of nonsurvivors from 8-24 hours before death versus survivors with an AUC of 0.894. The DL backcasting approach achieved discrimination with an AUC of 0.871 compared with the DL native model of nonsurvivors from 48-72 hours before death versus survivors with an AUC of 0.846. CONCLUSIONS: The DL backcasting approach could be used to simultaneously monitor changes in the electrolyte, metabolite, and acid-base parameters of patients who develop physiological instability during ICU treatment and predict the risk of death over a period of hours to days.


Assuntos
Equilíbrio Ácido-Base , Aprendizado Profundo , Eletrólitos/metabolismo , Unidades de Terapia Intensiva/estatística & dados numéricos , Adulto , Feminino , Humanos , Masculino , Estudos Retrospectivos , Medição de Risco
2.
Am J Physiol Renal Physiol ; 319(6): F966-F978, 2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-33073586

RESUMO

Circadian regulation of kidney function is involved in maintaining whole body homeostasis, and dysfunctional circadian rhythm can potentially be involved in disease development. Magnetic resonance imaging (MRI) provides reliable and reproducible repetitive estimates of kidney function noninvasively without the risk of adverse events associated with contrast agents and ionizing radiation. The purpose of this study was to estimate circadian variations in kidney function in healthy human subjects with MRI and to relate the findings to urinary excretions of electrolytes and markers of kidney function. Phase-contrast imaging, arterial spin labeling, and blood oxygen level-dependent transverse relaxation rate (R2*) mapping were used to assess total renal blood flow and regional perfusion as well as intrarenal oxygenation in eight female and eight male healthy volunteers every fourth hour during a 24-h period. Parallel with MRI scans, standard urinary and plasma parameters were quantified. Significant circadian variations of total renal blood flow were found over 24 h, with increasing flow from noon to midnight and decreasing flow during the night. In contrast, no circadian variation in intrarenal oxygenation was detected. Urinary excretions of electrolytes, osmotically active particles, creatinine, and urea all displayed circadian variations, peaking during the afternoon and evening hours. In conclusion, total renal blood flow and kidney function, as estimated from excretion of electrolytes and waste products, display profound circadian variations, whereas intrarenal oxygenation displays significantly less circadian variation.


Assuntos
Ritmo Circadiano/fisiologia , Rim/fisiologia , Imagem por Ressonância Magnética , Circulação Renal/fisiologia , Adulto , Eletrólitos/metabolismo , Feminino , Voluntários Saudáveis , Humanos , Masculino , Consumo de Oxigênio/fisiologia , Fatores Sexuais , Adulto Jovem
3.
Aquat Toxicol ; 226: 105561, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32688145

RESUMO

In the aquatic environment, metals are present as mixtures, therefore studies on mixture toxicity are crucial to thoroughly understand their toxic effects on aquatic organisms. Common carp (Cyprinus carpio) were used to assess the effects of short-term Cu(II) and Cd(II) mixtures, using a fixed concentration of one of the metals, representing 25 % of its individual 96h-LC50 (concentration lethal for 50 % of the population) combined with a variable concentration of the other metal corresponding to 10, 25 or 50 % of its 96h-LC50, and vice versa. Our results showed a fast Cu and Cd bioaccumulation, with the percentage of increase in the order gill > liver > carcass. An inhibitory effect of Cu on Cd uptake was observed; higher Cu concentrations at fixed Cd levels resulted in a decreased accumulation of Cd. The presence of the two metal ions resulted in losses of total Na, K and Ca. Fish tried to compensate for the Na loss through the induction of the genes coding for Na+/K+-ATPase and H+-ATPase. Additionally, a counterintuitive induction of the gene encoding the high affinity copper transporter (CTR1) occurred, while a downregulation was expected to prevent further metal ion uptake. An induction of defensive mechanisms, both metal ion binding protein and anti-oxidant defences, was observed. Despite the metal accumulation and electrolyte loss, the low mortality suggest that common carp is able to cope with these metal levels, at least during a one-week exposure.


Assuntos
Bioacumulação/efeitos dos fármacos , Cádmio/toxicidade , Carpas/metabolismo , Cobre/toxicidade , Homeostase/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Cádmio/metabolismo , Carpas/genética , Cobre/metabolismo , Transportador de Cobre 1/genética , Transportador de Cobre 1/metabolismo , Eletrólitos/metabolismo , Brânquias/efeitos dos fármacos , Brânquias/metabolismo , Transporte de Íons , Dose Letal Mediana , Potássio/metabolismo , Sódio/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Poluentes Químicos da Água/metabolismo
4.
Res Vet Sci ; 132: 42-48, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32480187

RESUMO

Objectives were to determine the effects of a product containing electrolytes, osmolytes, and energetic compounds (EOEC) on body temperature indices in heat-stressed (HS) Holstein cows. Lactating cows were assigned to 1 of 2 treatments: 1) a control diet (n = 10) or 2) a control diet supplemented with 113 g/d of EOEC (n = 10; Bovine BlueLite® Pellets; TechMix LLC, Stewart, MN). The trial consisted of 2 experimental periods (P). During P1 (4 d), cows were fed their respective treatments and housed in thermoneutral conditions. During P2 (4 d), HS was artificially induced using an electric heat blanket (EHB). Overall, HS markedly increased vaginal temperature (Tv), rectal temperature (Tr), skin temperature (Ts), and respiration rate (RR) (P < .01). There were no dietary treatment differences in Tv, Tr, or RR; however, during P2 EOEC-supplemented cows had increased Ts (0.8 °C; P = .04). Compared to P1, HS decreased DMI and milk yield (45 and 27%, respectively, P < .01) similarly amongst treatments. Relative to P1, circulating insulin decreased (41%; P = .04) in CON cows, whereas it remained unaffected in EOEC-supplemented cows, resulting in a 2-fold increase in EOEC compared with CON-fed cows (P < .01) during P2. Relative to P1, HS increased circulating non-esterified fatty acids (NEFA; 63%; P < .01). During P2, there tended to be a treatment by day interaction on circulating NEFA, as concentrations decreased from d 2 to 4 of P2 in EOEC-fed cows but continued to increase in CON cows. In summary, feeding EOEC altered some key aspects of energetic metabolism and increased Ts.


Assuntos
Temperatura Corporal/efeitos dos fármacos , Dieta/veterinária , Eletrólitos/metabolismo , Resposta ao Choque Térmico/efeitos dos fármacos , Lactação/efeitos dos fármacos , Ração Animal/análise , Animais , Bovinos , Suplementos Nutricionais/análise , Eletrólitos/administração & dosagem , Feminino , Distribuição Aleatória
5.
Crit Rev Oncol Hematol ; 151: 102974, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32416348

RESUMO

BACKGROUND: Aim of this meta-analysis was to determine the relative risk (RR) of electrolyte disorders (EDs) in advanced non-small cell lung cancer (aNSCLC) patients treated with immune check-point inhibitors (ICIs). METHODS: We searched for phase II/III randomized controlled trials (RCTs) comparing ICIs (alone or combined with chemotherapy) with standard chemotherapy in aNSCLC. Summary incidence and RR were calculated. RESULTS: Six RCTs with data on all-grade hyponatremia were identified (n = 3257). The incidence was 8.7 % in the study group and 4.9 % in the control group (RR 1.78, 95 %CI 1.12-2.80). Looking at all-grade hypokalemia, 7 RCTs were included (n = 4119). Incidence was 10.4 % in ICIs-treated patients and 5.9 % in the control arms (RR 1.62, 95 % CI 1.30-2.02). CONCLUSIONS: Treatment with ICIs in aNSCLC is associated with a significant increased risk of hyponatremia and hypokalemia compared to chemotherapy. Monitoring of electrolyte levels should be emphasized in this setting.


Assuntos
Antineoplásicos/uso terapêutico , Carcinoma Pulmonar de Células não Pequenas/complicações , Neoplasias Pulmonares/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/patologia , Eletrólitos/metabolismo , Humanos , Neoplasias Pulmonares/metabolismo
6.
J Vis Exp ; (159)2020 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-32421003

RESUMO

Dyshomeostasis of iron metabolism is accounted in the pathophysiological framework of numerous diseases, including cancer and several neurodegenerative conditions. Excessive iron results in free redox-active Fe(II) and can cause devastating effects within the cell like oxidative stress (OS) and death by lipid peroxidation known as ferroptosis (FPT). Therefore, quantitative measurements of ferrous (Fe(II)) and ferric (Fe(III)) iron rather than total Fe-determination is the key for closer insight into these detrimental processes. Since Fe(II)/(III) determinations can be hampered by fast redox-state shifts and low concentrations in relevant samples, like cerebrospinal fluid (CSF), methods should be available that analyze quickly and provide low limits of quantification (LOQ). Capillary electrophoresis (CE) offers the advantage of fast Fe(II)/Fe(III) separation and works without a stationary phase, which could interfere with the redox balance or cause analyte sticking. CE combined with inductively coupled plasma mass spectrometry (ICP-MS) as a detector offers further improvement of detection sensitivity and selectivity. The presented method uses 20 mM HCl as a background electrolyte and a voltage of +25 kV. Peak shapes and concentration detection limits are improved by conductivity-pH-stacking. For reduction of 56[ArO]+, ICP-MS was operated in the dynamic reaction cell (DRC) mode with NH3 as a reaction gas. The method achieves a limit of detection (LOD) of 3 µg/L. Due to stacking, higher injection volumes were possible without hampering separation but improving LOD. Calibrations related to peak area were linear up to 150 µg/L. Measurement precision was 2.2% (Fe(III)) to 3.5% (Fe(II)). Migration time precision was <3% for both species, determined in 1:2 diluted lysates of human neuroblastoma (SH-SY5Y) cells. Recovery experiments with standard addition revealed accuracy of 97% Fe(III) and 105 % Fe(II). In real-life bio-samples like CSF, migration time can vary according to varying conductivity (i.e., salinity). Thus, peak identification is confirmed by standard addition.


Assuntos
Eletrólitos/metabolismo , Eletroforese Capilar/métodos , Ferro/análise , Espectrometria de Massas/métodos , Neuroblastoma/metabolismo , Humanos , Oxirredução , Células Tumorais Cultivadas
7.
PLoS One ; 15(5): e0232051, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32433697

RESUMO

Dalbergia odorifera T. Chen seedlings do not grow well in the typical red soils of tropical regions. Eighteen culture substances filled with different substrate combinations and proportions of red soil, coconut coir powder, deciduous leaf powder, and sand were used as to determine their effects on the growth, root system development, dry matter accumulation and allocation, leaf relative electrolyte leakage, chlorophyll content, root superoxide dismutase activity, root malondialdehyde content, and total soluble sugar content of D. odorifera. Results demonstrated that different substrate combinations and proportions had different effects on the performance of D. odorifera. All mixed substrates were better than any single substrate. The suitable substrate combinations and proportions of sand, coconut coir powder, and deciduous leaf powder mixed with red soil improved the growth, root architecture, and physiological characteristics of D. odorifera seedling. For example, groups C1-2 (coconut coir/red soil = 2/2, v/v, the same below) and C3-2 (red soil/sand = 2/2) exerted the best effects on plant growth and biomass accumulation. Groups C1-2, C2-2 (deciduous leaf powder/red soil = 2/2), and C3-2 remarkably enhanced root system development. Group C6 (coconut coir/red soil/sand = 1/1/1) substantially promoted root nodule development. Group C3-1 (red soil/sand = 3/1) exhibited the best effects on physiological characteristics. On the basis of the comprehensive evaluation of Euclid's multidimensional space mathematical model, we found that the suitable substrate combinations followed the order of C1-2 > C3-1 > C2-2. This research provides scientific guidance for the proper seedling culture of D. odorifera and the rational utilization of solid wastes such as coconut coir and deciduous leaves of Ficus elastica.


Assuntos
Dalbergia/fisiologia , Solo/química , Biomassa , Clorofila/análise , Dalbergia/anatomia & histologia , Dalbergia/crescimento & desenvolvimento , Eletrólitos/metabolismo , Fertilizantes/análise , Malondialdeído/metabolismo , Folhas de Planta/química , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/enzimologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Plântula/anatomia & histologia , Plântula/crescimento & desenvolvimento , Plântula/fisiologia , Superóxido Dismutase/metabolismo
8.
Sci Rep ; 10(1): 6900, 2020 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-32327685

RESUMO

In this study, Ca2+ mediated NO signalling was studied in response to metalloid (As) stress in Brassica seedlings. Arsenic toxicity strongly suppressed the growth (fresh weight, root and shoot length), photosynthetic pigments, Chl a fluorescence indices (Kinetic traits: Fv, Fm, Fv/Fo, Fm/Fo, ФPo or Fv/Fm, Ψo, ФEo, PIABS, Area and N and redox status (AsA/DHA and GSH/GSSG ratios) of the cell; whereas energy flux traits: ABS/RC, TRo/RC, ETo/RC and DIo/RC along with Fo, Fo/Fv, Fo/Fm, ФDo and Sm) were enhanced. Further, addition of EGTA (Ca2+ scavenger) and LaCl3 (plasma membrane Ca2+ channel blocker) to As + Ca; while c‒PTIO (NO scavenger) and L‒NAME (NO synthase inhibitor) to As + SNP treated seedlings, siezed recovery on above parameters caused due to Ca2+ and NO supplementation, respectively to As stressed seedlings thereby indicating their signalling behaviour. Further, to investigate the link between Ca2+ and NO, when c‒PTIO and L‒NAME individually as well as in combination were supplemented to As + Ca treated seedlings; a sharp inhibition in above mentioned traits was observed even in presence of Ca2+, thereby signifying that NO plays crucial role in Ca2+ mediated signalling. In addition, As accumulation, ROS and their indices, antioxidant system, NO accumulation and thiol compounds were also studied that showed varied results.


Assuntos
Arsênico/toxicidade , Cálcio/metabolismo , Mostardeira/crescimento & desenvolvimento , Óxido Nítrico/metabolismo , Plântula/crescimento & desenvolvimento , Antioxidantes/metabolismo , Ácido Ascórbico/metabolismo , Carotenoides/metabolismo , Clorofila/metabolismo , Eletrólitos/metabolismo , Glutationa/metabolismo , Peróxido de Hidrogênio/metabolismo , Malondialdeído/metabolismo , Mostardeira/efeitos dos fármacos , Nitroprussiato/farmacologia , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Fenótipo , Fotossíntese/efeitos dos fármacos , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Plântula/efeitos dos fármacos , Compostos de Sulfidrila/metabolismo , Superóxidos/metabolismo
9.
Sci Rep ; 10(1): 6883, 2020 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-32327687

RESUMO

This research was conducted to understand the influence of foliar applied melatonin (0, 50, 100, 150 and 200 µM) on two Salvia species (Salvia nemorosa L., and Salvia reuterana Boiss) under conditions of water stress. Water stress was applied using a reduced irrigation strategy based on re-watering at 80%, 60% and 40% of the field capacity (FC). Increasing water stress, while significantly enhancing malondialdehyde (MDA), H2O2, electrolyte leakage, oxidized glutathione (GSSG), and total glutathione (GT), reduced glutathione (GSH), catalase (CAT), peroxidase (POD), superoxide dismutase (SOD) and glutathione reductase (GR) activities, which led to a marked reduction in fluorescence (Fv/Fm). Foliar application of melatonin alleviated the oxidative stress by increasing GT, CAT, POD, SOD and GR activities and reducing GSSG. In particular, melatonin heightened GSH content as well as the ratio of GSH/GSSG when compared to non-sprayed water stressed plants. Melatonin-treated plants had significantly lower SOD and POD activities than control plants under drought stress, while the CAT activity was enhanced with the foliar treatment. Essential oil yield of both Salvia species increased with the decrease in irrigation from 80% to 60% FC but diminished with the more severe water deficit (40% FC). Essential oil components of Salvia nemorosa were ß- caryophyllene, germacrene- B, spathulenol, and cis- ß- farnesene, while (E) - ß- ocimene, α- gurjnnene, germacrene-D, hexyl acetate and aromadendrene was the major constituents of Salvia reuterana. When plants were subjected to water deficit, melatonin treatment increased the concentration and composition of the essential oil. In particular, melatonin treatments improved the primary oil components in both species when compared to non-melatonin treated plants. In conclusion, reduced irrigation regimes as well as melatonin treatments resulted in a significant improvement of essential oil production and composition in both Salvia species.


Assuntos
Secas , Glutationa/metabolismo , Melatonina/farmacologia , Óleos Voláteis/metabolismo , Salvia/fisiologia , Estresse Fisiológico , Análise de Variância , Antioxidantes/metabolismo , Cloroplastos/efeitos dos fármacos , Cloroplastos/metabolismo , Análise por Conglomerados , Eletrólitos/metabolismo , Dissulfeto de Glutationa/metabolismo , Oxirredução/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Estresse Fisiológico/efeitos dos fármacos
10.
J Phys Chem Lett ; 11(8): 2941-2948, 2020 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-32223169

RESUMO

A highly efficient CO2 electrolysis system could be created by introducing biomass oxidation as an alternative anodic reaction to the sluggish oxygen evolution reaction in a CO2-saturated and near-neutral electrolyte. Here, we successfully demonstrate anodic biomass oxidation by synthesizing 5 nm nickel oxide nanoparticles (NiO NPs). NiO NPs show a unique electrocatalytic activity for 5-hydroxymethylfurfural (HMF) oxidation under near-neutral conditions, exhibiting an anodic current onset (1 mA cm-2) at 1.524 V versus the reversible hydrogen electrode and a total Faradaic efficiency of ≤70%. Electrokinetic and in situ ultraviolet-visible spectroscopic analyses suggest that a redox active nickel hydroxide species is formed on the surface of NiO electrocatalysts during HMF oxidation, and this oxidation of Ni(II) hydroxide to Ni(III) oxyhydroxide could be the rate-determining step. This mechanistic study of biomass oxidation in a CO2-saturated electrolyte provides insight into constructing a highly efficient system for the paired electrolysis of CO2 reduction and biomass oxidation.


Assuntos
Biomassa , Dióxido de Carbono/química , Eletrólise/métodos , Eletrólitos/química , Nanopartículas Metálicas/química , Níquel/química , Dióxido de Carbono/metabolismo , Técnicas Eletroquímicas/métodos , Eletrólitos/metabolismo , Níquel/metabolismo , Oxirredução
11.
Sci Rep ; 10(1): 6432, 2020 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-32286357

RESUMO

Soil amendments are known to promote several plant growth parameters. In many agro-ecosystems, water scarcity and drought induced phosphorus deficiency limits crop yield significantly. Considering the climate change scenario, drought and related stress factors will be even more severe endangering the global food security. Therefore, two parallel field trials were conducted to examine at what extent soil amendment of leonardite and humic acid would affect drought and phosphorus tolerance of maize. The treatments were: control (C: 100% A pan and 125 kg P ha-1), P deficiency (phosphorus stress (PS): 62.5 kg P ha-1), water deficit stress (water stress (WS): 67% A pan), and PS + WS (67% A pan and 62.5 kg P ha-1). Three organic amendments were (i) no amendment, (ii) 625 kg S + 750 kg leonardite ha-1 and (iii) 1250 kg S + 37.5 kg humic acid ha-1) tested on stress treatments. Drought and P deficiency reduced plant biomass, grain yield, chlorophyll content, Fv/Fm, RWC and antioxidant activity (superoxide dismutase, peroxidase, and catalase), but increased electrolyte leakage and leaf H2O2 in maize plants. The combined stress of drought and P deficiency decreased further related plant traits. Humic acid and leonardite enhanced leaf P and yield in maize plants under PS. A significant increase in related parameters was observed with humic acid and leonardite under WS. The largest increase in yield and plant traits in relation to humic acid and leonardite application was observed under combined stress situation. The use of sulfur-enriched amendments can be used effectively to maintain yield of maize crop in water limited calcareous soils.


Assuntos
Secas , Substâncias Húmicas/análise , Minerais/química , Fósforo/deficiência , Solo/química , Estresse Fisiológico , Enxofre/química , Zea mays/fisiologia , Fosfatase Ácida/metabolismo , Adaptação Fisiológica , Antioxidantes/metabolismo , Biomassa , Catalase/metabolismo , Clorofila/metabolismo , Eletrólitos/metabolismo , Fluorescência , Peróxido de Hidrogênio/metabolismo , Malondialdeído/metabolismo , Estresse Oxidativo , Peroxidase/metabolismo , Folhas de Planta/metabolismo , Brotos de Planta/crescimento & desenvolvimento , Superóxido Dismutase/metabolismo , Água , Zea mays/crescimento & desenvolvimento
12.
Food Chem ; 322: 126753, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32283366

RESUMO

This paper investigated the effects of radio-frequency (RF) energy and conventional hot-water blanching (95 °C for 2 min) on the peroxidase (POD) activity, physiochemical properties, and changes in the cellular morphology of stem lettuce. The relative residual POD activity significantly decreased (P < 0.05) from 66.03% to 6.46% with increased RF heating temperature (65 °C-85 °C). The weight loss (3.06%-7.64%), color, texture, relative electrolyte leakage (23.45%-67.90%), and residual vitamin C content (72.22%-16.67%) significantly changed (P < 0.05) with increased RF heating temperature (65 °C-85 °C). Micrographs indicated that the changes in physiochemical property can be attributed to the destruction of cell membranes, loss of cell turgor, reduced rigidity of cell walls, and loose adhesion between adjacent cells. Samples treated by RF heating at 75 °C showed lesser cell damage and better nutrient retention than those treated by hot-water blanching at a similar level of POD inactivation.


Assuntos
Alface/metabolismo , Peroxidase/metabolismo , Ondas de Rádio , Ácido Ascórbico/análise , Parede Celular/química , Eletrólitos/metabolismo , Temperatura Alta , Alface/efeitos da radiação , Alface/ultraestrutura , Paladar , Água/química
13.
Int J Radiat Biol ; 96(7): 919-928, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32159411

RESUMO

Purpose: To evaluate the effects of polyethylene glycol (PEG) 6000 pretreatment on growth and physiological responses of eukaryotic microalga Chlorella vulgaris exposed to ionizing irradiation.Materials and methods: The microalgal cells pretreated with different PEG concentrations (0, 5, 10 and 20%) and then exposed to 300 Gray gamma irradiation at a dose rate of 0.5 Gy s-1. The various growth and physiological parameters including algal growth, cell size, the degree of electrolyte leakage (EL) and lipid peroxidation, the content of pigments and proline and the activity of antioxidant enzymes under gamma-free or 300 Gray gamma irradiation conditions were examined.Results: The results showed that PEG stimulated a higher growth and cell size under both stress-free and gamma-stress conditions. The maximum growth and cell size was reported when the algae was pretreated with 10% PEG. A relative increase of catalase activity was observed in all samples after exposing to gamma irradiation. However, the highest value was recorded for the gamma-radiated algae pretreated with 10% PEG. In the absence of PEG, gamma irradiation induced a significant reduction in ascorbate peroxidase activity, but with PEG pretreatment, the enzyme activity remained constant or even increased after gamma irradiation. On the other hand, although gamma irradiation stress generally suppressed the activity of superoxide dismutase in all cells, pretreating the algae with PEG could diminish this suppressing effect at all applied concentrations. Compared to the PEG-free controls, a lower rate of chlorophylls and membrane integrity loss was shown in the PEG-treated algae when exposed to gamma stress. Total carotenoid content in PEG-treated algae was also similar under both gamma-free and gamma-radiated conditions. A PEG-independent increase in proline accumulation was reported under gamma-irradiation treatment.Conclusions: Overall, the results suggested that PEG pretreatment could improve gamma-irradiation tolerance in C. vulgaris probably by stimulating a range of enzymatic and non-enzymatic reactive oxygen species scavenging systems. The microalgae may also consume PEG to break down and use it as an alternative source of carbon during stress which should be further studied in detail.


Assuntos
Chlorella vulgaris/efeitos dos fármacos , Chlorella vulgaris/efeitos da radiação , Raios gama/efeitos adversos , Polietilenoglicóis/farmacologia , Protetores contra Radiação/farmacologia , Carotenoides/metabolismo , Chlorella vulgaris/crescimento & desenvolvimento , Chlorella vulgaris/metabolismo , Clorofila/metabolismo , Relação Dose-Resposta a Droga , Eletrólitos/metabolismo , Malondialdeído/metabolismo , Prolina/metabolismo
14.
Eur J Appl Physiol ; 120(4): 719-752, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32124007

RESUMO

PURPOSE: The purpose of this paper is to review the physiological mechanisms determining eccrine sweat composition to assess the utility of sweat as a proxy for blood or as a potential biomarker of human health or nutritional/physiological status. METHODS: This narrative review includes the major sweat electrolytes (sodium, chloride, and potassium), other micronutrients (e.g., calcium, magnesium, iron, copper, zinc, vitamins), metabolites (e.g., glucose, lactate, ammonia, urea, bicarbonate, amino acids, ethanol), and other compounds (e.g., cytokines and cortisol). RESULTS: Ion membrane transport mechanisms for sodium and chloride are well established, but the mechanisms of secretion and/or reabsorption for most other sweat solutes are still equivocal. Correlations between sweat and blood have not been established for most constituents, with perhaps the exception of ethanol. With respect to sweat diagnostics, it is well accepted that elevated sweat sodium and chloride is a useful screening tool for cystic fibrosis. However, sweat electrolyte concentrations are not predictive of hydration status or sweating rate. Sweat metabolite concentrations are not a reliable biomarker for exercise intensity or other physiological stressors. To date, glucose, cytokine, and cortisol research is too limited to suggest that sweat is a useful surrogate for blood. CONCLUSION: Final sweat composition is not only influenced by extracellular solute concentrations, but also mechanisms of secretion and/or reabsorption, sweat flow rate, byproducts of sweat gland metabolism, skin surface contamination, and sebum secretions, among other factors related to methodology. Future research that accounts for these confounding factors is needed to address the existing gaps in the literature.


Assuntos
Glândulas Écrinas/metabolismo , Suor/química , Sudorese , Aclimatação , Eletrólitos/metabolismo , Humanos , Micronutrientes/metabolismo , Condicionamento Físico Humano , Cloreto de Sódio na Dieta/metabolismo , Manejo de Espécimes , Suor/metabolismo
15.
Nat Rev Nephrol ; 16(6): 337-351, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32127698

RESUMO

The kidney is a remarkable organ that accomplishes the challenge of removing waste from the body and simultaneously regulating electrolyte and water balance. Pro-urine flows through the nephron in a highly dynamic manner and adjustment of the reabsorption rates of water and ions to the variable tubular flow is required for electrolyte homeostasis. Renal epithelial cells sense the tubular flow by mechanosensation. Interest in this phenomenon has increased in the past decade since the acknowledgement of primary cilia as antennae that sense renal tubular flow. However, the significance of tubular flow sensing for electrolyte handling is largely unknown. Signal transduction pathways regulating flow-sensitive physiological responses involve calcium, purinergic and nitric oxide signalling, and are considered to have an important role in renal electrolyte handling. Given that mechanosensation of tubular flow is an integral role of the nephron, defective tubular flow sensing is probably involved in renal disease. Studies investigating tubular flow and electrolyte transport differ in their methodology, subsequently hampering translational validity. This Review provides the basis for understanding electrolyte disorders originating from altered tubular flow sensing as a result of pathological conditions.


Assuntos
Sinalização do Cálcio/fisiologia , Túbulos Renais/metabolismo , Óxido Nítrico/metabolismo , Receptores Purinérgicos/metabolismo , Reabsorção Renal/fisiologia , Equilíbrio Hidroeletrolítico/fisiologia , Desequilíbrio Hidroeletrolítico/metabolismo , Água Corporal/metabolismo , Cílios , Eletrólitos/metabolismo , Células Epiteliais , Taxa de Filtração Glomerular , Humanos , Pelve Renal , Mecanotransdução Celular , Microfluídica , Transdução de Sinais
16.
J Zoo Wildl Med ; 51(1): 102-109, 2020 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-32212552

RESUMO

Anesthesia is commonly employed in aquatic medicine to facilitate physical exams, diagnostics, and surgical interventions. Tricaine methanesulfonate (MS-222) is the most commonly used anesthetic for fish and is currently the only anesthetic approved by the US Food and Drug Administration Center for Veterinary Medicine for food-producing fish. Despite the frequency of anesthetic procedures in fish, anesthetic monitoring remains rudimentary in many facilities. This study evaluated the impact on blood gases, acid-base balance, and electrolytes in koi (Cyprinus carpio) anesthetized at concentrations of 100 mg/L and 150 mg/L MS-222. Blood samples from 25 fish per treatment were collected at 5 and 20 min of anesthetic immersion. Forty-nine of 50 fish recovered uneventfully from anesthesia; one fish did not recover and was euthanatized. Results showed significant increases in partial pressure of carbon dioxide (pCO2) (P = 0.006) and hyperglycemia (P = <0.0001) with increasing anesthetic concentration and time under anesthesia and a significant decrease in partial pressure of oxygen (pO2) with increased anesthetic time (P = 0.021). There were several electrolyte changes observed with both increasing anesthetic time and concentration. All electrolytes except potassium remained within published reference ranges for koi, while potassium showed a significant decrease in concentration associated with anesthetic time and concentration. The results of this study indicate that MS-222 at 100 mg/L and 150 mg/L represent safe anesthetic concentrations for koi undergoing minimally invasive diagnostics; however, koi anesthetized with MS-222 at a concentration of 150 mg/L experienced more significant changes in blood gases, acid-base balance, and electrolyte concentrations.


Assuntos
Equilíbrio Ácido-Base , Aminobenzoatos/administração & dosagem , Anestesia/veterinária , Anestésicos/administração & dosagem , Carpas/fisiologia , Eletrólitos/metabolismo , Anestesia/métodos , Animais , Gasometria/veterinária , Carpas/sangue , Relação Dose-Resposta a Droga , Fatores de Tempo , Equilíbrio Hidroeletrolítico
18.
Nat Biotechnol ; 38(2): 189-198, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31932726

RESUMO

The ability to preserve metabolically active livers ex vivo for 1 week or more could allow repair of poor-quality livers that would otherwise be declined for transplantation. Current approaches for normothermic perfusion can preserve human livers for only 24 h. Here we report a liver perfusion machine that integrates multiple core physiological functions, including automated management of glucose levels and oxygenation, waste-product removal and hematocrit control. We developed the machine in a stepwise fashion using pig livers. Study of multiple ex vivo parameters and early phase reperfusion in vivo demonstrated the viability of pig livers perfused for 1 week without the need for additional blood products or perfusate exchange. We tested the approach on ten injured human livers that had been declined for transplantation by all European centers. After a 7-d perfusion, six of the human livers showed preserved function as indicated by bile production, synthesis of coagulation factors, maintained cellular energy (ATP) and intact liver structure.


Assuntos
Fígado/lesões , Perfusão/instrumentação , Preservação Biológica , Trifosfato de Adenosina/metabolismo , Alarminas/metabolismo , Animais , Biomarcadores/metabolismo , Eletrólitos/metabolismo , Glucose/metabolismo , Hemodinâmica , Hemólise , Humanos , Fígado/fisiopatologia , Oxigênio/metabolismo , Consumo de Oxigênio , Veia Porta/metabolismo , Reperfusão , Suínos
19.
Medicine (Baltimore) ; 99(2): e18709, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31914079

RESUMO

Kidney handling of electrolytes varies in different stages of chronic kidney disease (CKD). Diabetes mellitus (DM) plays an important role in CKD. Fractional excretion (FE) is an important means in clinical practice. The relationship between FE of electrolytes in patients at different stages of CKD is worth further investigating.We designed a cross-sectional study in 1 teaching hospital, consecutive CKD patients were enrolled between February 2016 and January 2017. Including clinical demographic features, laboratory examination including spot urine electrolytes, blood biochemistries, and relevant medications were determined.A total of 762 CKD patients completed the study. Of these, 218 (28.6%) had DM. Participants were grouped according to estimated glomerular filtration rate into 7 categories: hyperfiltration (HF), CKD1, CKD2, CKD3a, CKD3b, CKD4, and CKD5. Groups HF, CKD1, 2, 3a, 3b, 4 and 5 contained 83, 143, 192, 94, 82, 82, and 86 patients, respectively. FE of electrolytes tended to increase along with the decline of renal function (CKD1-CKD5) (P < .001). The relationship was similar between the DM and non-DM groups. Diabetic patients demonstrated higher FE of magnesium compared with non-DM subjects at CKD2 and CKD5 (P < .05).CKD patients showed a progressive increase in the FE of electrolytes; FE of magnesium seemed to increase more among diabetic patients with CKD, and could be a potential predictor of CKD progression.


Assuntos
Eletrólitos/metabolismo , Taxa de Filtração Glomerular/fisiologia , Insuficiência Renal Crônica/fisiopatologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Progressão da Doença , Eletrólitos/urina , Feminino , Humanos , Magnésio/metabolismo , Masculino , Pessoa de Meia-Idade , Índice de Gravidade de Doença
20.
J Med Case Rep ; 14(1): 15, 2020 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-31955708

RESUMO

BACKGROUND: In clinical practice, both the history and laboratory testing are paramount to making an accurate diagnosis. Situations in which laboratory findings and patient history are not congruent pose a diagnostic dilemma. We report a case of a young woman presenting with a myriad of electrolyte and acid-base disorders. Difficulty in reaching a unifying diagnosis persisted due to discordant patient history. We believe this case shows that lab findings will clearly portray the problems a patient has and should be given more credence in a case where the history is discordant with lab findings. CASE PRESENTATION: A 28-year-old Hispanic American woman presented to the emergency room of our institution with a complaint of painless and sudden onset of stiffness in her upper and lower limbs. Associated weakness worse in the distal limbs was also reported. She experienced shortness of breath with minimal exertion, diaphoresis, and anxiety. Her vital signs revealed tachycardia without corresponding fever. She was conscious, oriented, and alert. Her physical exam revealed dry mucous membranes and warm extremities. She denied recent consumption of a large carbohydrate meal, diarrhea, vomiting, use of laxatives, and use of alcohol or recreational drugs. She vaguely described two previous similar episodes in the last 7 months that spontaneously resolved. Her medical history was significant only for hypothyroidism treated with daily levothyroxine tablets. Laboratory analysis revealed the following abnormalities: an elevated anion gap with significant lactate, hypokalemia, hypomagnesemia, elevated mean corpuscular volume, elevated mean cell hemoglobin, and elevated liver enzymes with aspartate aminotransferase/alanine aminotransferase ratio > 2. She was hydrated with balanced crystalloids, and her electrolyte deficiencies corrected. The etiology of her multiple electrolyte abnormalities was unclear because alcohol use was vehemently denied. Extensive evaluation for causes of electrolyte disorder was undertaken, which was unrevealing. On further interrogation, she admitted to recent alcohol intoxication and several episodes of vomiting before presentation. She was advised to refrain from alcohol use and discharged afterward. CONCLUSION: Both patient history and laboratory analysis have a role in identifying and confirming a diagnosis. In cases in which laboratory tests are incongruous with reported history, making a unifying diagnosis can be challenging or delayed. The importance of taking a comprehensive history cannot be overemphasized, but history provided by patients may be prone to intentional or unintentional distortion, whereas laboratory findings are more objective. The case presented underscores why the lab findings should be given credence in cases in which there is discordance between lab results and the provided patient history.


Assuntos
Desequilíbrio Ácido-Base/etiologia , Técnicas de Laboratório Clínico , Eletrólitos/metabolismo , Gravidade do Paciente , Adulto , Consumo de Bebidas Alcoólicas/efeitos adversos , Feminino , Hispano-Americanos , Humanos , Hipocalcemia/etiologia , Hipopotassemia/etiologia , Hipofosfatemia/etiologia , Deficiência de Magnésio/congênito , Deficiência de Magnésio/etiologia , Vômito/complicações
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA