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1.
Biol Trace Elem Res ; 202(2): 513-526, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37099221

RESUMO

Although conjugated linoleic acid (CLA) can promote human health, its content in milk is insufficient to have a significant impact. The majority of the CLA in milk is produced endogenously by the mammary gland. However, research on improving its content through nutrient-induced endogenous synthesis is relatively scarce. Previous research found that the key enzyme, stearoyl-CoA desaturase (SCD) for the synthesis of CLA, can be expressed more actively in bovine mammary epithelial cells (MAC-T) when lithium chloride (LiCl) is present. This study investigated whether LiCl can encourage CLA synthesis in MAC-T cells. The results showed that LiCl effectively increased SCD and proteasome α5 subunit (PSMA5) protein expression in MAC-T cells as well as the content of CLA and its endogenous synthesis index. LiCl enhanced the expression of proliferator-activated receptor-γ (PPARγ), sterol regulatory element-binding protein 1 (SREBP1), and its downstream enzymes acetyl CoA carboxylase (ACC), fatty acid synthase (FASN), lipoprotein lipase (LPL), and Perilipin 2 (PLIN2). The addition of LiCl significantly enhanced p-GSK-3ß, ß-catenin, p-ß-catenin protein expression, hypoxia-inducible factor-1α (HIF-1α), and downregulation factor genes for mRNA expression (P < 0.05). These findings highlight that LiCl can increase the expression of SCD and PSMA5 by activating the transcription of HIF-1α, Wnt/ß-catenin, and the SREBP1 signaling pathways to promote the conversion of trans-vaccenic acid (TVA) to the endogenous synthesis of CLA. This data suggests that the exogenous addition of nutrients can increase CLA content in milk through pertinent signaling pathways.


Assuntos
Ácidos Linoleicos Conjugados , Cloreto de Lítio , Humanos , Animais , Bovinos , Cloreto de Lítio/farmacologia , Cloreto de Lítio/análise , Cloreto de Lítio/metabolismo , beta Catenina/metabolismo , Ácidos Linoleicos Conjugados/análise , Ácidos Linoleicos Conjugados/metabolismo , Ácidos Linoleicos Conjugados/farmacologia , Glicogênio Sintase Quinase 3 beta/análise , Glicogênio Sintase Quinase 3 beta/metabolismo , Glicogênio Sintase Quinase 3 beta/farmacologia , Glândulas Mamárias Animais/metabolismo , Leite/química , Estearoil-CoA Dessaturase , Células Epiteliais/metabolismo , Ácidos Graxos/metabolismo
2.
Metabolomics ; 16(10): 112, 2020 10 10.
Artigo em Inglês | MEDLINE | ID: mdl-33037948

RESUMO

INTRODUCTION: Headspace gas chromatography-mass spectrometry (HS-GC-MS) is widely considered the gold standard of quantitative fecal VOC analysis. However, guidelines providing general recommendations for bioanalytical method application in research and clinical setting are lacking. OBJECTIVES: To propose an evidence-based research protocol for fecal VOC analysis by HS-GC-MS, based on extensive testing of instrumental and sampling conditions on detection and quantification limits, linearity, accuracy and repeatability of VOC outcome. METHODS: The influence of the following variables were assessed: addition of different salt solutions, injection temperature, injection speed, injection volume, septum use, use of calibration curves and fecal sample mass. Ultimately, the optimal sample preparation was assessed using fecal samples from healthy preterm infants. Fecal VOC analysis in this specific population has potential as diagnostic biomarkers, but available amount of feces is limited here, so optimization of VOC extraction is of importance. RESULTS: We demonstrated that addition of lithium chloride enhanced the release of polar compounds (e.g. small alcohols) into the headspace. Second, a linear relationship between injection volume, speed and temperature, and fecal sample mass on the abundance of VOC was demonstrated. Furthermore, the use of a septum preserved 90% of the non-polar compounds. By application of optimal instrumental and sampling conditions, a maximum of 320 unique compounds consisting of 14 different chemical classes could be detected. CONCLUSIONS: These findings may contribute to standardized analysis of fecal VOC by HS-GC-MS, facilitating future application of fecal VOC in clinical practice.


Assuntos
Fezes/química , Manejo de Espécimes/métodos , Compostos Orgânicos Voláteis/análise , Feminino , Cromatografia Gasosa-Espectrometria de Massas/métodos , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Cloreto de Lítio/análise , Cloreto de Lítio/metabolismo , Masculino , Reprodutibilidade dos Testes , Microextração em Fase Sólida/métodos , Compostos Orgânicos Voláteis/química
3.
Meat Sci ; 135: 123-128, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28968555

RESUMO

The use of Li salts in foods has been prohibited due to their negative effects on central nervous system; however, they might still be used especially in meat products as Na substitutes. Lithium can be toxic and even lethal at higher concentrations and it is not approved in foods. The present study focuses on Li analysis in meatballs by using laser induced breakdown spectroscopy (LIBS). Meatball samples were analyzed using LIBS and flame atomic absorption spectroscopy. Calibration curves were obtained by utilizing Li emission lines at 610nm and 670nm for univariate calibration. The results showed that Li calibration curve at 670nm provided successful determination of Li with 0.965 of R2 and 4.64ppm of limit of detection (LOD) value. While Li Calibration curve obtained using emission line at 610nm generated R2 of 0.991 and LOD of 22.6ppm, calibration curve obtained at 670nm below 1300ppm generated R2 of 0.965 and LOD of 4.64ppm.


Assuntos
Lasers , Cloreto de Lítio/análise , Espectrofotometria Atômica/métodos , Animais , Calibragem , Bovinos , Produtos da Carne/análise
4.
Environ Microbiol ; 19(9): 3745-3754, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28752915

RESUMO

Salar de Uyuni (SdU), with a geological history that reflects 50 000 years of climate change, is the largest hypersaline salt flat on Earth and is estimated to be the biggest lithium reservoir in the world. Its salinity reaches saturation levels for NaCl, a kosmotropic salt, and high concentrations of MgCL2 and LiCl, both salts considered important chaotrophic stressors. In addition, extreme temperatures, anoxic conditions, high UV irradiance, high albedo and extremely low concentrations of phosphorous, make SdU a unique natural extreme environment in which to contrast hypotheses about limiting factors of life diversification. Geophysical studies of brines from different sampling stations show that water activity is rather constant along SdU. Geochemical measurements show significant differences in magnesium concentration, ranging from 0.2 to 2M. This work analyses the prokaryotic diversity and community structure at four SdU sampling stations, selected according to their location and ionic composition. Prokaryotic communities were composed of both Archaea (with members of the classes Halobacteria, Thermoplasmata and Nanohaloarchaea, from the Euryarchaeota and Nanohaloarcheota phyla respectively) and Bacteria (mainly belonging to Bacteroidetes and Proteobacteria phyla). The important differences in composition of microbial communities inversely correlate with Mg2+ concentration, suggesting that prokaryotic diversity at SdU is chaotropic dependent.


Assuntos
Archaea/classificação , Archaea/isolamento & purificação , Bactérias/classificação , Bactérias/isolamento & purificação , Ambientes Extremos , Archaea/genética , Bactérias/genética , Biodiversidade , Bolívia , Cloreto de Lítio/análise , Cloreto de Magnésio/análise , RNA Ribossômico 16S/genética , Salinidade , Sais/análise , Cloreto de Sódio/análise
5.
Regul Toxicol Pharmacol ; 75: 66-71, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26721340

RESUMO

This study investigated whether there was a difference in amounts of dentifrice ingested by children based on age using pea-sized instructions. The study had a randomized, single-blinded, 3-period, crossover design modelled after Barnhart et al. (1974) with one regular-flavored and two specially-flavored dentifrices used ad libitum. Subjects were enrolled in three groups: 2-4, 5-7, and 8-12 years. They were instructed to brush at home as they would normally with each dentifrice for 3 weeks (9 weeks total). On weekly study-site visits, subjects brushed with the assigned dentifrice containing a lithium marker to measure the amount of dentifrice ingested and used. Averaging across dentifrices, amounts ingested were: 0.205 g (2-4 yr), 0.125 g (5-7 yr) and 0.135 g (8-12 yr), demonstrating 2-4 year-olds ingested significantly more than older children (p ≤ 0.002). Averaging across dentifrices, amounts used were: 0.524 g (2-4 yr), 0.741 g (5-7 yr) and 0.978 g (8-12 yr) suggesting an age-related effect (p < 0.01). Findings also showed that ingestion amount for specially-flavored dentifrices may increase relative to regular-flavored dentifrice for children 2-7 years-old. This research demonstrated that dentifrice ingestion amount decreased significantly with age while usage amount increased with age. Importantly, ingestion and usage levels in younger children reflect "pea-sized" direction and were numerically lower than historical levels reported prior to this direction.


Assuntos
Dentifrícios , Ingestão de Alimentos , Fatores Etários , Criança , Pré-Escolar , Estudos Cross-Over , Dentifrícios/análise , Exposição Ambiental/análise , Feminino , Aromatizantes , Humanos , Cloreto de Lítio/análise , Masculino , Método Simples-Cego
6.
Appl Microbiol Biotechnol ; 100(10): 4423-33, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26754817

RESUMO

The Pal/Rim pathway essential for fungal adaptation to ambient pH has been unexplored in Beauveria bassiana, a classic fungal entomopathogen. Here, we show the characterized Pal pathway comprising transcription factor PacC and upstream six Pal partners (PalA/B/C/F/H/I) in B. bassiana. Their coding genes were all transcribed most abundantly in standard wild-type culture under the alkaline condition of pH 9. Deletion of pacC or each pal gene resulted in a significant delay of culture acidification in a minimal broth (initial pH = 7.3). This delay concurred with altered accumulation levels of intra/extracellular organic acids and drastically depressed expression of some enzyme genes required for the syntheses of oxalic and lactic acids. Our deletion mutants except ΔpalI showed growth defects and maximal sensitivity to NaCl, KCl, LiCl, or sorbitol at pH 9, an alkaline condition leading to fragmented vacuoles in their hyphal cells exposed to osmotic stress. In these mutants, conidiation was significantly facilitated at pH 3 more than at pH 7 but suppressed slightly at pH 9. Mild virulence defects also occurred in the absence of pacC or any pal gene. These changes were restored by targeted gene complementation. Taken together, PacC and Pal partners regulate the growth, conidiation, and osmotolerance of B. bassiana in a pH-dependent manner, highlighting their vitality for the fungal pH response.


Assuntos
Adaptação Fisiológica/genética , Beauveria/crescimento & desenvolvimento , Beauveria/genética , Proteínas Fúngicas/genética , Pressão Osmótica , Proteínas Fúngicas/metabolismo , Deleção de Genes , Regulação Fúngica da Expressão Gênica , Concentração de Íons de Hidrogênio , Hifas/citologia , Hifas/metabolismo , Microbiologia Industrial , Ácido Láctico/biossíntese , Cloreto de Lítio/análise , Ácido Oxálico/metabolismo , Cloreto de Potássio/análise , Cloreto de Sódio/análise , Estresse Fisiológico/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
7.
Electrophoresis ; 36(6): 875-83, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25522336

RESUMO

To realize portable systems for routine measurements in point-of-care settings, MCE methods are required to be robust across many single-use chips. While it is well-known internal standards (ISTDs) improve run-to-run precision, a systematic investigation is necessary to determine the significance of chip-to-chip imprecision in MCE and how ISTDs account for it. This paper addresses this question by exploring the reproducibility of Na quantification across six basic, in-house fabricated microchips. A dataset of 900 electrophoerograms was collected from analyzing five concentrations of NaCl with two ISTDs (CsCl and LiCl). While both improved the peak area reproducibility, the Na/Cs ratio was superior to the Na/Li ratio (improving the RSD by a factor of 2-4, depending on the Na concentration). We attribute this to the significant variation in microchannel surface properties, which was accounted for by cesium but not lithium. Microchip dimension and detector variations were only a few percent, and could be improved through commercial fabrication over in-house made microchips. These results demonstrate that ISTDs not only correct for intrachip imprecision, but are also a viable means to correct for chip-to-chip imprecision inherent in disposable, point-of-care MCE devices. However, as expected, the internal standard must be carefully chosen.


Assuntos
Eletroforese em Microchip/instrumentação , Eletroforese em Microchip/normas , Desenho de Equipamento , Modelos Lineares , Cloreto de Lítio/análise , Cloreto de Lítio/química , Modelos Químicos , Padrões de Referência , Reprodutibilidade dos Testes , Cloreto de Sódio/análise , Cloreto de Sódio/química
8.
Water Sci Technol ; 64(1): 132-8, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22053467

RESUMO

Water authorities interested in the evaluation of the structural state of a sewer must quantify leakage to plan strategic intervention. However, the quantification of the exfiltration and the localisation of structural damage are challenging tasks that usually require expensive and time-consuming inspections. Herein, we report one of the first applications of the QUEST-C method to quantify the exfiltration in a continuously operating sewer by dosing two chemical tracers, sodium bromide (NaBr) and lithium chloride (LiCl). The method was applied at the catchment scale in a 14-year-old sewer in Rome, Italy. Preliminary laboratory tests, field measurements, and numerical simulations showed that reliable results require the QUEST-C method to be applied to sewers without lateral inflows, during periods of quasi-steady flow, and that the travel time of the NaBr tracer is minimised. Three sewer reaches were tested and the estimated exfiltration, as a fraction of the dry weather flow (DWF), increased from 0.128 in the agricultural area to 0.208 in the urban area. Although our estimates are at the lower end of the range given in the literature (0.01-0.56 DWF), the exfiltration was not negligible, and interventions should focus on the sewers in urban areas. This illustrates the capability of the QUEST-C method to guide strategic intervention at low cost and without an interruption of sewer operation. However, careful interpretation of the results is recommended for sewers with many lateral inflows, where leakage may be overestimated.


Assuntos
Drenagem Sanitária , Monitoramento Ambiental/métodos , Brometos/análise , Monitoramento Ambiental/instrumentação , Cloreto de Lítio/análise , Reprodutibilidade dos Testes , Cidade de Roma , Esgotos/análise , Compostos de Sódio/análise , Eliminação de Resíduos Líquidos
9.
Zh Obshch Biol ; 71(4): 359-68, 2010.
Artigo em Russo | MEDLINE | ID: mdl-20865934

RESUMO

The data from scientific publications on excretory activity of herbs root endings were analyzed, along with the data on the role of polyvalent metals cations in stabilization of humus substances (HS) of soil organic mineral complex. On the base of the analysis a working hypothesis was proposed considering root endings influence on fractional composition of soil organic components. To detect the changes taking place in soil HS, the chromatographic fractionation method was chosen. The soil aggregates stuck to root endings of germinating barley seed were washed off, and the washouts were used as the samples for the analysis. The soil from the weighed portion was dissolved directly with extenuating concentrations of LiCl and Li2SO4 alkaline solution. The fractionation was carried out in a chromatographic column. Some changes were detected in optical density of chernozem and dark-grey forest soil leached out after 1-2 days of barley seeds germination. Besides, the experiment showed that the content of organic carbon in HS changes as well.


Assuntos
Germinação , Hordeum/crescimento & desenvolvimento , Raízes de Plantas/crescimento & desenvolvimento , Sementes/crescimento & desenvolvimento , Solo/análise , Carbono/análise , Carbono/metabolismo , Fracionamento Químico , Cromatografia , Hordeum/metabolismo , Cloreto de Lítio/análise , Cloreto de Lítio/metabolismo , Compostos de Lítio/metabolismo , Raízes de Plantas/metabolismo , Sementes/metabolismo , Sulfatos/metabolismo
10.
Curr Microbiol ; 61(4): 335-9, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20300937

RESUMO

The virulence of Candida species depends on many environmental conditions, including extracellular pH and concentration of alkali metal cations. Tests of the tolerance/sensitivity of four pathogenic Candida species (C. albicans, C. dubliniensis, C. glabrata, and C. parapsilosis) to alkali metal cations under various growth conditions revealed significant differences among these species. Though all of them can be classified as rather osmotolerant yeast species, they exhibit different levels of tolerance to different salts. C. parapsilosis and C. albicans are the most salt-tolerant in general; C. dubliniensis is the least tolerant on rich YPD media and C. glabrata on acidic (pH 3.5) minimal YNB medium. C. dubliniensis is relatively salt-sensitive in spite of its ability to maintain as high intracellular K(+)/Na(+) ratio as its highly salt-tolerant relative C. albicans. On the other hand, C. parapsilosis can grow in the presence of very high external NaCl concentrations in spite of its high intracellular Na(+) concentrations (and thus lower K(+)/Na(+) ratio) and thus resembles salt-tolerant (halophilic) Debaryomyces hansenii.


Assuntos
Candida/fisiologia , Candida/patogenicidade , Tolerância ao Sal/fisiologia , Candida/metabolismo , Candida albicans/patogenicidade , Candida albicans/fisiologia , Candida glabrata/patogenicidade , Candida glabrata/fisiologia , Cloreto de Lítio/análise , Cloreto de Lítio/farmacologia , Cloreto de Potássio/análise , Cloreto de Potássio/farmacologia , Sais , Cloreto de Sódio/análise , Cloreto de Sódio/farmacologia , Especificidade da Espécie , Virulência
11.
J Hazard Mater ; 160(2-3): 634-7, 2008 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-18440139

RESUMO

In this study, a vacuum distillation of a mixture of LiCl-KCl eutectic salt and rare-earth oxidative precipitates was performed to separate a pure LiCl-KCl eutectic salt from the mixture. Also, a dechlorination and oxidation of the rare-earth oxychlorides was carried out to stabilize a final waste form. The mixture was distilled under a range of 710-759.5Torr of a reduced pressure at a fixed heating rate of 4 degrees C/min and the LiCl-KCl eutectic salt was completely separated from the mixture. The required time for the salt distillation and the starting temperature for the salt vaporization were lowered with a reduction in the pressure. Dechlorination and oxidation of the rare-earth oxychlorides was completed at a temperature below 1300 degrees C and this was dependent on the partial pressure of O2. The rare-earth oxychlorides (NdOCl/PrOCl) were transformed to oxides (Nd2O3/PrO2) during the dechlorination and oxidation process. These results will be utilized to design a concept for a process for recycling the waste salt from an electrorefining process.


Assuntos
Cloreto de Lítio/análise , Metais Terras Raras/química , Cloreto de Potássio/análise , Ácido Hipocloroso/química , Oxirredução , Temperatura , Difração de Raios X
12.
Ecotoxicol Environ Saf ; 68(3): 419-25, 2007 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17509685

RESUMO

The objective of this study is to discern the effects of increased waterborne lithium and potassium on rainbow trout gill histology, lipid composition, and enzyme activity. The study aims to elucidate the effects of these ions in the laboratory in concentrations similar to those prevailing in a forest lake Poppalijärvi in a contaminated mining area in NW Russia. Under the lithium and potassium exposure, the fish were further stressed by high pH (8.2 as in Lake Poppalijärvi) and lack of food. These multiple stress conditions altered the gill membrane fluidity by increasing sphingomyelin (5.5+/-0.6 compared to 2.9+/-0.3% in the control) and reducing cholesterol (4+/-1 compared to 17+/-3 mg g(-1) in the control). The total ATPase activity tended to be higher in the lithium-potassium-exposed group (46+/-6 compared to 34+/-2 micromol Pi h(-1) mg(-1)protein in the control). Lithium toxicity was lowered here by the protective role of higher potassium contents.


Assuntos
Carbonatos/toxicidade , Brânquias/efeitos dos fármacos , Cloreto de Lítio/toxicidade , Oncorhynchus mykiss/metabolismo , Potássio/toxicidade , Sulfatos/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Carbonatos/análise , Colesterol/metabolismo , Proteínas de Peixes/metabolismo , Privação de Alimentos , Água Doce/química , Brânquias/enzimologia , Brânquias/metabolismo , Brânquias/patologia , Concentração de Íons de Hidrogênio , Metabolismo dos Lipídeos/efeitos dos fármacos , Cloreto de Lítio/análise , Fluidez de Membrana/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/patologia , Potássio/análise , ATPase Trocadora de Sódio-Potássio/metabolismo , Esfingomielinas/metabolismo , Sulfatos/análise , Fatores de Tempo , Poluentes Químicos da Água/análise
13.
Anal Sci ; 22(9): 1175-8, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16966805

RESUMO

Ion-exchange chromatography using a high-capacity anion exchanger with UV detection was applied to the determination of nitrate in seawater. Major ions in seawater samples did not affect the peak shape and the retention time of the nitrate when an alkaline metal cation-chloride solution was used as an eluent at high concentrations (0.5-2 mol/l). At a wavelength of 220 nm, the peak of bromide was very small because of low absorption, while its separation from the nitrate peak was good at high concentrations. Among the eluents tested, lithium chloride gave the best separation of nitrate from bromide. It was estimated that the lithium ion had the least potential for ion-pair formation with nitrate, and its retention time was prolonged compared with the retention times when using other cations; with bromide and nitrite, such an effect was not observed. The results of shipboard seawater nitrate determination by our method in the South Pacific Ocean and Antarctic Sea showed good agreement with those by the conventional photometric method using continuous flow.


Assuntos
Técnicas de Química Analítica/métodos , Cromatografia por Troca Iônica/métodos , Cloreto de Lítio/análise , Nitratos/análise , Água do Mar , Ânions , Brometos/química , Cátions , Técnicas de Química Analítica/instrumentação , Cloretos/química , Relação Dose-Resposta a Droga , Íons , Lítio/química , Cloreto de Lítio/química , Nitratos/química , Nitritos/química , Raios Ultravioleta
14.
Biomacromolecules ; 6(3): 1258-65, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15877340

RESUMO

The SEC-MALS-QELS (size-exclusion chromatography equipped with multiangle light scattering and quasi-elastic light scattering detectors) method using lithium chloride/N,N-dimethylacetamide (LiCl/DMAc) and LiCl/1,3-dimethyl-2-imidazolidinone (LiCl/DMI) as mobile phases was applied to cellulose and cellulose tricarbanilate (CTC) samples with various average degree of polymerization (DP) values. Molecular conformations of cellulose and CTC in the solvents were then discussed and compared on the basis of the relationships between the radii of gyration (R(g,z) or S(2)(z)(1/2)), the hydrodynamic radii (R(h,z)), and weight-average DP (DP(w)) or the contour lengths (L(w)). The Benoit-Doty theory for wormlike polymer chains was applied to the R(g) vs L(w) data obtained, and the theoretical curves with Kuhn segment lengths l(K) of around 18 nm were found to fit the data of both cellulose and CTC molecules in the solvents. It was concluded from the obtained results that both cellulose and CTC molecules have conformations essentially identical to each other in the solvents; they behave as typical semiflexible chains in good solvents.


Assuntos
Amidas/análise , Celulose/análise , Cromatografia em Gel/métodos , Luz , Cloreto de Lítio/análise , Amidas/química , Configuração de Carboidratos , Celulose/química , Cloreto de Lítio/química , Conformação Molecular , Espalhamento de Radiação , Soluções
15.
Ground Water ; 43(1): 133-7, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15726931

RESUMO

This paper presents the design of the passive-discrete water sampler (PDWS) which has been developed to facilitate investigations of flow partitioning in fractured rocks. The PDWS continuously isolates seeping water into discrete samples while monitoring the seepage rate. The PDWS was used in a flow and transport experiment that investigated fracture-matrix interactions. During the experiment, a mix of conservative tracers with significantly different diffusion coefficients (lithium bromide [LiBr] and pentafluorobenzoic acid [PFBA]) was introduced along a fault located in fractured tuffs, and water seeping through the lower end of the fault was collected by the PDWS and analyzed for tracer concentrations. Preliminary results from this investigation show that samples of effluent captured by the PDWS effectively retained temporal changes in the chemical signature, while providing seepage rates.


Assuntos
Monitoramento Ambiental/métodos , Sedimentos Geológicos , Movimentos da Água , Poluentes Radioativos da Água/análise , Benzoatos/análise , Monitoramento Ambiental/instrumentação , Cloreto de Lítio/análise
16.
Langmuir ; 20(11): 4621-8, 2004 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-15969174

RESUMO

The influence of LiCl solutions on liposomal and surface-supported phosphatidylcholine/water systems (dipalmitoylphosphatidylcholine (DPPC) and 1-palmitoyl-2-oleoylphosphatidylcholine (POPC), respectively) has been studied by small-angle X-ray techniques. In liposomal dispersions of DPPC, an osmotically stressed liquid-crystalline phase, denoted as Lalpha osm, forms readily after rapid mixing with salt solutions. The transition from Lalpha -->Lalpha osm proceeds in two steps. The first step takes place within seconds and is due to water diffusion from the liposome into the bulk solution. The second, slower process (minutes) can be attributed to the relaxation of initially deformed intermediate liposomes into spherical ones. In experiments with aligned lipid bilayers supported on silicon wafers, it was possible to reproducibly exchange different concentrations of LiCl solutions on a single sample and to determine the lattice changes by time-resolved X-ray scattering at grazing incidence. Independently of the deposition technique (spray- or spin-coating, respectively), none of the investigated POPC samples displayed an osmotically stressed liquid-crystalline phase. While liposomes can be considered nearly defect-free, supported bilayer stacks show a high abundance of defects, such as oily streaks typical of the Lalpha phase. Thus, the alkali ions are free to diffuse into the interbilayer water regions and to cause a slight increase of the bilayer separation (about 1 Angstroms). It is concluded that low to medium concentrations of Li+ ions partially screen the attractive van der Waals force between adjacent membrane layers. However, upon annealing the defect regions or regions of high curvature in the oriented lipid matrix, e.g. by low amounts of oleyl alcohol (OA), the system is able to sense osmotic stress upon addition of a salt solution.


Assuntos
Lipídeos/química , Cloreto de Lítio/análise , Difração de Raios X/métodos , 1,2-Dipalmitoilfosfatidilcolina/química , Cinética , Fosfatidilcolinas/química , Espalhamento de Radiação , Soluções/química , Temperatura , Raios X
17.
Ther Drug Monit ; 25(3): 364-6, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12766565

RESUMO

Lithium is a drug of choice for the management of bipolar disorder, a disease frequently affecting women in their childbearing years. Unfortunately, this drug has typically been contraindicated in nursing women. Data in humans are limited with respect to the use of this drug in lactating women, and early reports suggest high excretion into milk. The purpose of this report was to verify the excretion of lithium into human milk and to assess infant safety after breast-feeding. The authors found wide interpatient variability in lithium dose offered to the infant through breast milk (from 0% to 30% of maternal weight-adjusted dose), indicating that therapeutic drug monitoring of lithium in milk and/or in infant's blood, coupled with close monitoring of adverse effects, is a rational approach. Since therapeutic drug monitoring of lithium is routine, physicians caring for these women and infants should be encouraged to individualize their recommendations.


Assuntos
Monitoramento de Medicamentos/métodos , Cloreto de Lítio/análise , Leite Humano/química , Transtorno Bipolar/tratamento farmacológico , Aleitamento Materno/estatística & dados numéricos , Intervalos de Confiança , Monitoramento de Medicamentos/estatística & dados numéricos , Feminino , Humanos , Recém-Nascido , Cloreto de Lítio/farmacologia , Cloreto de Lítio/uso terapêutico , Leite Humano/efeitos dos fármacos , Gravidez
18.
Clin Diagn Lab Immunol ; 2(1): 57-61, 1995 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-7719914

RESUMO

Local immunological defense mechanisms in the cervicovaginal mucosa currently remain incompletely defined, especially from a quantitative point of view. Addition of an inert substance, lithium chloride (LiCl), into the washing buffer used to carry out the vaginal washing for collecting cervicovaginal secretions and measurement of its concentration with a flame absorption spectrophotometer, before and after the specimen is sampled, permits the quantification of the volume of cervicovaginal secretions collected and the approximation of the dilution factor of a soluble component introduced by the washing. Lithium, at a concentration of 10 mM, gives the best precision of measurement and has no effect on the results of the immunoassays. In a population of 27 nonpregnant women (age range, 18 to 45 years), the volume of cervicovaginal secretions collected by vaginal washing with 3 ml of LiCl-phosphate-buffered saline was 12% +/- 3.2% (mean +/- standard deviation) of the total volume and showed large interindividual variations (range, 5.6 to 18.8%); the mean dilution factor of a soluble component from the vaginal secretions was 9.9% +/- 2.8% (range, 6.3 to 18.8%). According to the date of the menstrual cycle, the mean volume of collected cervicovaginal secretions was significantly increased in the luteal phase in comparison with the follicular phase; conversely, the mean dilution factor of a soluble component was more important in the follicular than in the luteal phase. These features strengthen the need to quantify accurately the dilution factor introduced by vaginal washing when studying cervicovaginal immunity.


Assuntos
Líquidos Corporais/imunologia , Colo do Útero/metabolismo , Vagina , Adolescente , Adulto , Colo do Útero/imunologia , Feminino , Fase Folicular/imunologia , Anticorpos Anti-HIV/análise , Proteína gp120 do Envelope de HIV/imunologia , Infecções por HIV/imunologia , HIV-1/imunologia , Humanos , Técnicas Imunoenzimáticas , Imunoglobulina G/análise , Cloreto de Lítio/análise , Fase Luteal/imunologia , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Irrigação Terapêutica
19.
Braz J Med Biol Res ; 25(9): 937-42, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1342841

RESUMO

1. The participation of special nephron segments in the renal control of sodium handling after adrenergic stimulation was investigated by determining lithium clearance in groups of 5-12 male Wistar rats (230-300 g) microinjected with noradrenaline into the lateral hypothalamic area (LHA). 2. Microinjection of noradrenaline (12.5 to 100.0 nmol/microliters) into the LHA promoted a significant decrease in proximal sodium reabsorption (controls, 86.5 +/- 1.3; 12.5, 81.4 +/- 2.0; 25.0, 72.6 +/- 2.4; 50.0, 75.4 +/- 1.8 and 100.0, 77.2 +/- 1.7%) and a dose-related increase in distal sodium reabsorption (control, 13.4 +/- 1.6; 12.5, 18.4 +/- 1,25.0, 26.9 +/- 2.9; 50.0, 24.1 +/- 2.7; 100.0, 22.1 +/- 1.9%) with no significant changes in creatinine clearance. Fractional sodium reabsorption after different noradrenaline concentrations was significantly reduced in the proximal nephron sites up to the concentration of 25.0 nmol/microliter. Beyond this concentration, a smaller but progressive increase in fractional sodium reabsorption was observed in the post-proximal segment. 3. These findings suggest an effective participation of proximal and post-proximal nephrons in natriuresis after lateral hypothalamic noradrenergic stimulation.


Assuntos
Região Hipotalâmica Lateral/efeitos dos fármacos , Rim/efeitos dos fármacos , Natriurese/efeitos dos fármacos , Receptores Adrenérgicos/efeitos dos fármacos , Análise de Variância , Animais , Creatinina/análise , Relação Dose-Resposta a Droga , Região Hipotalâmica Lateral/fisiologia , Rim/fisiologia , Cloreto de Lítio/análise , Masculino , Microinjeções , Norepinefrina/administração & dosagem , Norepinefrina/farmacologia , Potássio/análise , Ratos , Receptores Adrenérgicos/fisiologia , Sódio/análise , Estimulação Química
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