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1.
Food Chem ; 371: 131190, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-34583175

RESUMO

Urea, sodium dodecyl sulfate (SDS) and ß-mercaptoethanol (2-ME) were used to monitor the roles of hydrogen bonds, hydrophobic interactions and disulfide bonds in frozen egg yolk. Yolk samples were prepared with a denaturant, and the textural characteristics, turbidity properties, protein patterns and structures were analysed. The results showed that SDS or 2-ME addition to egg yolk promoted its turbidity and texture properties, but urea changed the turbidity differently. SDS-PAGE results showed that yolk protein patterns with urea slightly reduced the amount of high molecular weight substances, whereas SDS and 2-ME addition increased the amount. ATR-FTIR spectroscopy revealed that the protein secondary structures changed from ordered structures to random coils. The texture properties were correlated with the protein secondary structure, especially ß-sheets and ß-turns. Thus, the three bond dissociation reagents induced protein denaturation. Hydrogen bonds were the critical force affecting frozen egg yolk gelation, followed by hydrophobic interactions and disulfide bonds.


Assuntos
Proteínas do Ovo , Gema de Ovo , Eletroforese em Gel de Poliacrilamida , Congelamento , Indicadores e Reagentes , Estrutura Secundária de Proteína
2.
Food Chem ; 369: 130947, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34479015

RESUMO

Synthetic dyes can cause many health problems, and their use as food additives is rigorously regulated worldwide. Two methods for the determination of synthetic dyes in food are described in this article. The visual qualitative expression method was based on the extraction of synthetic dyes using a liquid anion exchanger (0.01 M solution of trioctylmethylammonium chloride in chloroform). Using this reagent, an optimal transition of 15 anionic synthetic dyes from the aqueous to the organic phase was achieved (R > 99.8%). It was applicable for testing food that must not contain synthetic dyes (wines, juices, etc.) in a very short time (5-10 min). In the case of colouring of the organic phase, identification and quantification was carried out using the HPLC-DAD method described. The rapid and simple method allows for simultaneous determination of 16 synthetic dyes from all food types. The LOD and LOQ ranged from 0.026 to 0.086 µg mL-1 and from 0.077 to 0.262 µg mL-1 respectively, and recovery was 83.7-107.5%. Hypothesis: anionic synthetic dyes have hydrophobic properties, as a result they are retained on the non-polar stationary phase of the chromatographic column and are easily extracted from aqueous solutions by liquid anion exchangers.


Assuntos
Corantes , Aditivos Alimentares , Ânions , Cromatografia Líquida de Alta Pressão , Indicadores e Reagentes
3.
J Pharm Biomed Anal ; 207: 114395, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34628292

RESUMO

For the robust analysis of N,N-Carbonyldiimidazole (CDI), its derivatization into a more stable compound may be needed. Herein, the reaction of CDI with N-benzylmethylamine followed by LC-UV quantitative analysis was explored. Reaction conditions as well as LC method feasibility were demonstrated by qualification of selectivity from other impurities and reagents, linearity across a range of 0.05-0.15%w/w, spike and recovery across a range of 0.05-0.15%w/w, reaction reproducibility with various samples, reagents and analytical chemists, and sample stability of over 24 h. Rapid and quantitative derivatization of residual CDI was achieved at 0.1% w/w relative to the synthetic product under consideration. A fit-for-purpose limit test using a RPLC-UV method as an in-process control for the reaction completion of product, at scale, was successfully implemented and executed.


Assuntos
Imidazóis , Indicadores e Reagentes , Reprodutibilidade dos Testes
4.
Talanta ; 237: 122964, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34736689

RESUMO

We describe a reagent-free acid-base titration method, in which only water is added and the titrant is online electrodialytically produced. Electrodialytic eluent generator, a well-established technique in ion chromatography to produce high purity base or acid eluent through precise control of an electric current, has been for the first time used for titration, termed as electrodialytic titrant generator (ETG). Three kinds of titrants produced by ETG have been demonstrated, including potassium hydroxide, methanesulfuric acid and sulfuric acid. A series of titrants with different concentration up to at least 140 mM (e.g. KOH) could be accurately and reproducibly obtained by manipulating current and the KOH titrant showed extremely high purity. The titration results achieved by ETG were in a good agreement with those obtained by the regular way and their ratio was in the range of 0.9918 and 1.0034. Good accuracy and precision were achieved for ETG titration, as indicated by 2.2% of relative error and 0.17% of relative standard error. Its utility was demonstrated to measure pKa-differentiated capacity of anion exchange resins.


Assuntos
Água , Cromatografia por Troca Iônica , Indicadores e Reagentes
5.
J Nanosci Nanotechnol ; 21(6): 3630-3633, 2021 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-34739815

RESUMO

Animal health issues are important for farming community in agriculture. Small ruminant populations such as goats and sheep often get affected with contagious diseases. Peste des petits ruminants caused by a virus which need to be detected quickly to isolate affected animals and stop the spread of disease. The H protein of Peste des petits ruminants virus has sialic acid specific receptor, therefore sialic acid reduce and stabilized gold-nanoparticles were synthesize by a simple one pot method and without chemically modifying the sialic acid. The gold nanoparticles showed targetspecific aggregation with viral particles via hemagglutinin-sialic acid binding. The PPR virus was readily detected at the dilution of 10-6 by sialic acid-AuNPs. While comparing with the standard monoclonal antibody based test used for the detection of Peste des petits ruminants virus, sialic acid-AuNPs gave detection faster in less than 2 minute.


Assuntos
Doenças das Cabras , Nanopartículas Metálicas , Peste dos Pequenos Ruminantes , Vírus da Peste dos Pequenos Ruminantes , Animais , Doenças das Cabras/diagnóstico , Ouro , Indicadores e Reagentes , Ácido N-Acetilneuramínico , Peste dos Pequenos Ruminantes/diagnóstico , Ovinos
6.
Anal Chim Acta ; 1188: 339158, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34794561

RESUMO

A paper-based colourimetric assay for the detection of alanine transaminase has been developed. In the presence of alanine transaminase, 2,4-dinitrophenyl hydrazine changes to pyruvate hydrazone leading to a colour change from pale yellow to dark yellow. Reaction conditions were optimized using absorption spectroscopic studies. Hydrophobic patterns on the Whatman chromatographic paper were created by wax printing, and the reagents were drop cast at the reagent zone. On the paper device, the intensity of the yellow colour increases with ALT concentration in the range of 20-140 U/L in human serum. For the quantification of ALT, coloured images were captured using a digital camera and were processed with Image J software. The machine learning approach was also explored for the ALT analysis by training with colour images of the paper device and testing using a cross-validation procedure. The results obtained with real clinical samples on the paper device showed good accuracy of less than 5% relative error with the clinical lab results. Furthermore, the paper device shows high selectivity to ALT in the presence of various interfering species in blood serum with a sensitivity of 0.261 a.u/(U/L), a detection limit of 4.12 U/L, and precise results with an RSD of less than 7%. For the testing of whole blood, a plasma separation membrane was integrated with the patterned paper.


Assuntos
Colorimetria , Aprendizado Profundo , Alanina Transaminase , Humanos , Indicadores e Reagentes , Papel
7.
Anal Chem ; 93(45): 14929-14933, 2021 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-34730331

RESUMO

Screening the metabolites of emerging organic contaminants (EOCs) from complicated biological matrices is an important but challenging task. Although stable isotope labeling (SIL) is frequently used to facilitate the identification of contaminant metabolites from redundant interfering components, the isotopically labeled reagents are expensive and difficult to synthesize, which greatly constrains the application of the SIL method. Herein, a new online noncovalent tagging method was developed for screening the metabolites of 1H-benzotriazol (BT) based on the characteristic structural moieties reserved in the metabolites. By selecting ß-cyclodextrin (ß-CD) as a macrocyclic tagging reagent, metabolites with the reserved moiety were expected to exhibit a characteristic shift of the mass-to-charge ratio (Δm/z = 1134.3698) after being noncovalently tagged by ß-CD. Based on the characteristic mass shift, the suspected features were reduced by 1 order of magnitude, as numerous interfering species that could not be effectively tagged by ß-CD were excluded. From these suspected features, two metabolites of BT that have not been reported before were successfully screened out. The significant characteristic mass shift caused by the noncovalent tagging method is easier to identify with more confidence than the previously reported SIL method. Besides, noncovalent tagging reagents can be much more accessible and less expensive than isotopically labeled reagents. Hence, this online noncovalent tagging method can be an intriguing alternative to the conventional SIL method.


Assuntos
Marcação por Isótopo , Indicadores e Reagentes , Íons
8.
Chimia (Aarau) ; 75(11): 923-935, 2021 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-34798914

RESUMO

Fluoroalkylations have received increasing attention in the academic and industrial environment due to the particular properties of the active ingredients that are strongly influenced by fluoroalkyl substituents. The inherent difficulties of introducing a fluoroalkyl substituent into advanced intermediates has triggered the development of an enormous number of specialized reagents, which, however, are often not suitable for large scale applications. In contrast to this reagent based fluoroalkylation approach, the direct activation of industrially readily available fluoroalkyl halides could be more suitable for a large-scale process. In this way the dithionite initiated fluoroalkylation as well as newly developed catalytically activated fluoroalkylation protocols were considered for industrial large-scale applications.


Assuntos
Indicadores e Reagentes
9.
Rinsho Ketsueki ; 62(10): 1515-1518, 2021.
Artigo em Japonês | MEDLINE | ID: mdl-34732626

RESUMO

We report a case of pseudo-prolongation of activated partial thromboplastin time (APTT), which was suspected to be caused by an animal-derived phospholipid. A 78-year-old woman was referred to our hospital because of an unexplained APTT prolongation. She had compensated alcoholic liver cirrhosis, with modestly decreased platelet count and normal prothrombin time, and no bleeding tendency. The APTT was 66 seconds in a test using phospholipid extracted from rabbit brain but was 34.9 seconds with synthetic phospholipids. The artifactual pseudo-prolongation of the APTT was seemingly attributable to the susceptibility of the test reagents to low factor XII levels. Thus, tests with different APTT reagents would be useful to physicians in the diagnosis of similar cases.


Assuntos
Transtornos da Coagulação Sanguínea , Animais , Testes de Coagulação Sanguínea , Feminino , Humanos , Indicadores e Reagentes , Tempo de Tromboplastina Parcial , Tempo de Protrombina , Coelhos
10.
BMC Cancer ; 21(1): 1087, 2021 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-34625031

RESUMO

BACKGROUND: Cancer remains one of the leading causes of death worldwide, despite the possibilities to detect early onset of the most common cancer types. The search for the optimal therapy is complicated by the cancer diversity within tumors and the unsynchronized development of cancerous cells. Therefore, it is necessary to characterize cancer cell populations after treatment has been applied, because cancer recurrence is not rare. In our research, we concentrated on small cancer cell subpopulation (microcells) that has a potential to be cancer resistance source. Previously made experiments has shown that these cells in small numbers form in specific circumstances after anticancer treatment. METHODS: In experiments described in this research, the anticancer agents' paclitaxel and doxorubicin were used to stimulate the induction of microcells in fibroblast, cervix adenocarcinoma, and melanoma cell lines. Mainly for the formation of microcells in melanoma cells. The drug-stimulated cells were then characterized in terms of their formation efficiency, morphology, and metabolic activity. RESULTS: We observed the development of cancer microcells and green fluorescent protein (GFP) transfection efficiency after stress. In the time-lapse experiment, we observed microcell formation through a renewal process and GFP expression in the microcells. Additionally, the microcells were viable after anticancer treatment, as indicated by the nicotinamide adenine dinucleotide hydrogen phosphate (NADPH) enzyme activity assay results. Taken together, these findings indicate that cancer microcells are viable and capable of resisting the stress induced by anticancer drugs, and these cells are prone to chemical substance uptake from the environment. CONCLUSION: Microcells are not only common to a specific cancer type, but can be found in any tumor type. This study could help to understand cancer emergence and recurrence. The appearance of microcells in the studied cancer cell population could be an indicator of the individual anticancer therapy effectiveness and patient survival.


Assuntos
Antineoplásicos/farmacologia , Resistencia a Medicamentos Antineoplásicos , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Contagem de Células , Linhagem Celular Tumoral , Núcleo Celular/ultraestrutura , Autorrenovação Celular , Sobrevivência Celular/efeitos dos fármacos , Proteínas de Ligação a DNA/metabolismo , Doxorrubicina/farmacologia , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Feminino , Fibroblastos/efeitos dos fármacos , Proteínas de Fluorescência Verde/metabolismo , Células HeLa , Humanos , Indicadores e Reagentes/farmacocinética , Melanoma/metabolismo , Melanoma/patologia , Microscopia Eletrônica , NADP/metabolismo , Recidiva Local de Neoplasia/metabolismo , Recidiva Local de Neoplasia/patologia , Neoplasias/metabolismo , Neoplasias/ultraestrutura , Vermelho Neutro/farmacocinética , Paclitaxel/farmacologia , Estresse Fisiológico , Imagem com Lapso de Tempo , Fatores de Transcrição/metabolismo , Transfecção , Neoplasias do Colo do Útero/tratamento farmacológico , Neoplasias do Colo do Útero/metabolismo , Neoplasias do Colo do Útero/patologia
11.
J Vis Exp ; (175)2021 09 24.
Artigo em Inglês | MEDLINE | ID: mdl-34633363

RESUMO

Measuring Wnt expression levels is essential when trying to identify or test new Wnt therapeutic targets. Previous studies have shown that canonical Wnt signaling operates via a dosage-driven mechanism, motivating the need to study and measure Wnt signaling in various cell types. Although several reporter models have been proposed to represent physiological Wnt expression, either the genetic context or the reporter protein highly influenced the validity, accuracy, and flexibility of these tools. This paper describes methods for acquiring and analyzing data obtained with the Axin2-mTurquoise2 mouse Wnt reporter model, which contains a mutated Axin2em1Fstl allele. This model facilitates the study of endogenous canonical Wnt signaling in individual cells over a wide range of Wnt activity. This protocol describes how to fully appreciate Axin2-mTurquoise2 reporter activity using cell population analysis of the hematopoietic system, combined with cell surface markers or ß-catenin intracellular staining. These procedures serve as a base for implementation and reproduction in other tissues or cells of interest. By combining fluorescence-activated cell sorting and confocal imaging, distinct canonical Wnt expression levels can be visualized. The recommended measurement and analysis strategies provide quantitative data on the fluorescent expression levels for precise assessment of canonical Wnt signaling. These methods will be useful for researchers who want to use the Axin2-mTurquise2 model for canonical Wnt expression patterns.


Assuntos
Timócitos , Via de Sinalização Wnt , Animais , Proteína Axina/genética , Citometria de Fluxo , Indicadores e Reagentes , Camundongos
12.
Molecules ; 26(20)2021 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-34684903

RESUMO

A new HPLC method for the simultaneous quantitative analysis of adenosine triphosphate (ATP), adenosine diphosphate (ADP), and adenosine monophosphate (AMP) was developed and validated. ATP, ADP, and AMP were extracted from human bronchial epithelial cells with a rapid extraction procedure and separated with a C18 column (3 × 150 mm, 2.7 µm) using isocratic elution with a mobile phase consisting of 50 mM of potassium hydrogen phosphate (pH 6.80). The absorbance was monitored at 254 nm. The calibration curves were linear in 0.2 to 10 µM, selective, precise, and accurate. This method allowed us to quantify the nucleotides from two cell models: differentiated NHBE primary cells grown at the air-liquid interface (ALI) and BEAS-2B cell line. Our study highlighted the development of a sensitive, simple, and green analytical method that is faster and less expensive than other existing methods to measure ATP, ADP, and AMP and can be carried out on 2D and 3D cell models.


Assuntos
Nucleotídeos de Adenina/metabolismo , Brônquios/metabolismo , Células Epiteliais/metabolismo , Linhagem Celular , Cromatografia Líquida de Alta Pressão/métodos , Humanos , Indicadores e Reagentes/metabolismo
13.
Molecules ; 26(20)2021 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-34684843

RESUMO

The analysis of total vitamin C content in food is most frequently performed by reducing dehydroascorbic acid to ascorbic acid, which is then assayed with the technique of high-performance liquid chromatography combined with spectrophotometric detection. Tris(2-carboxyethyl)phosphine is currently the only agent in use that efficiently reduces dehydroascorbic acid at pH < 2. Therefore, there is a continued need to search for new reducing agents that will display a high reactivity and stability in acidic solutions. The objective of the study was to verify the applicability of unithiol and tris(hydroxypropyl)phosphine for a reducing dehydroascorbic acid in an extraction medium with pH < 2. The conducted validation of the newly developed method of determining the total content of vitamin C using tris(hydroxypropyl)phosphine indicates its applicability for food analysis. The method allows obtaining equivalent results compared to the method based on the use of tris(2-carboxyethyl)phosphine. The low efficiency of dehydroascorbic acid reduction with the use of unithiol does not allow its application as a new reducing agent in vitamin C analysis.


Assuntos
Ácido Ascórbico/química , Ácido Desidroascórbico/química , Substâncias Redutoras/química , Cromatografia Líquida de Alta Pressão/métodos , Alimentos , Análise de Alimentos/métodos , Indicadores e Reagentes/química , Fosfinas/química
14.
Se Pu ; 39(9): 1021-1029, 2021 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-34486842

RESUMO

Ion-pair reversed-phase liquid chromatography (IP-RPLC) enhances separation by adding ion-pair reagents to the mobile phase, thereby improving the retention of oppositely charged solutes. IP-RPLC is primarily used for the separation and analysis of strongly ionized compounds. In IP-RPLC, researchers often focus more on the influence of the counter-ion type and concentration, buffer salt concentration and pH, and column temperature, on the retention behavior of solutes. However, the effects of the buffer salt type and non-counter ions in ion-pair reagents on the retention behavior of solutes have rarely been investigated. Accordingly, in this work, the effects of buffer salt types and non-counter ions on the retention behavior of strongly ionized compounds were investigated by IP-RPLC using 14 sulfonic acid compounds as model compounds. Experiments were performed using a silica-based C18 column with methanol as the organic modifier. In the first type of experiment, tetrabutylammonium bromide was kept unchanged as the ion-pair reagent in the mobile phase, and ammonium dihydrogen phosphate, ammonium chloride, and ammonium acetate were used as buffer salts, respectively. The retention factor (k) was obtained at different methanol ratios, and linear solvent strength (LSS) models were established to determine the log kw (logarithm of retention factors of solutes when 100% aqueous phases were used as the mobile phase) and S (intercept of the LSS model) values of each solute. All solutes exhibited the highest log kw with the ammonium chloride buffer system; most compounds also exhibited the highest S values with this system, except for 1,5-naphthalenedisulfonic acid, 4-methylbenzenesulfonic acid, 5-amino-2-nanphthalenesulfonic acid, and 4-hydroxybenzenesulfonic acid. However, the chromatographic hydrophobic indices (CHIs, log kw/S) of the solutes with different buffer salts were approximately equal. In the second type of experiment, ammonium dihydrogen phosphate was kept unchanged as the buffer salt in the mobile phase, and tetrabutylammonium bromide, tetrabutylammonium dihydrogen phosphate, tetrabutylammonium hydrogen sulfate, tetrabutylammonium nitrate, and tetrabutylammonium acetate were used as ion-pair reagents, respectively. Almost all solutes exhibited the highest S with the tetrabutylammonium acetate system, indicating that weakly ionized anions (such as acetate ions) in ion-pair reagents will improve the S values of sulfonic acid compounds. Interestingly, the CHIs of the solutes were almost the same for solutes with different non-counter ions. These results suggest that both, the buffer salt types and non-counter ions, influence the log kw and S values of sulfonic acid compounds. Comparison of the retention behavior of solutes with different mobile phases suggested ion-pair mechanisms as well as dynamic ion-exchange mechanisms plays role in the IP-RPLC retention of sulfonic acid compounds. In addition, with all the experimental mobile phases, the apparent n-octanol/water partition coefficient (log D) presented a good linear correlation with log kw, S, and CHI, respectively, by the introduction of structure-related descriptors such as charge (ne), Abraham solvation parameters (A and B), and the polar surface area (PSA). Considering the differences in the log kw and S values obtained with different buffer salts and non-counter ions, the CHIs were relatively stable; therefore, the CHI is more suitable for establishing a quantitative structure-retention relationship (QSRR) model in IP-RPLC, compared to log kw and S.


Assuntos
Cromatografia de Fase Reversa , Cromatografia Líquida de Alta Pressão , Concentração de Íons de Hidrogênio , Indicadores e Reagentes , Íons
15.
Se Pu ; 39(9): 1030-1037, 2021 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-34486843

RESUMO

Portable analytical instruments find extensive application in on-site examination because of their significant advantages: these instruments are convenient and easy-to-carry, leading to high time-effectiveness, and involve low reagent consumption. We report a portable micro-liquid chromatograph (p-µLC) that was designed and fabricated in our laboratory. The p-µLC integrates homemade dual large-thrust syringe pumps for delivering the mobile phase, a capillary polymer monolithic column as the stationary phase for the separation of the target analytes, and a specially designed dual-functional optical-fiber microflow-cell for online detection. The dual-thrust syringe pumps can realize isocratic and/or gradient elution as well as reloading of the mobile phase, with flow rates ranging from 0.025 µL/min to 5.6 mL/min and the maximum working pressure of 4.5 MPa. The polymethacrylate based C-18 monolithic column facilitates the separation of small organic molecules and biomacromolecules. A homemade high-power light emission diode (LED) light source and a modified xenon flash lamp are assembled as the light source module. The dual-functional detector consists of an optical fiber microflow-cell with a self-focusing lens and a light-guiding capillary, light source module, and a small-sized grating spectrometer with an output wavelength range of 400-680 nm for the LED light source and 220-700 nm for the xenon flash lamp, enabling online detection of the absorption and fluorescence spectra of the analytes from 220 to 700 nm. A bifurcated optical fiber bundle is prepared and used to connect the light source, microflow-cell, and grating spectrometer so that the incident light leading-in and the fluorescence/scatting light leading-out can be realized simultaneously. The junction end of the bifurcated optical fiber bundles connects to one end of the light path of the microflow-cell, and a straight-through optical fiber connects another end of the microflow-cell. In the UV-Vis absorption mode, the straight-through optical fiber reads out the transmitted light, while in the fluorescence mode, the excitation light beam from the light source irradiates the sample solution in the flow-cell via one branch of the bifurcated optic fiber bundles. The fluorescence leading-out via the other branch of the bifurcated optical fiber bundles in the opposite direction of the excitation light beam is read out by the spectrometer. All the large-thrust syringe pumps and flow-path, capillary monolithic column, and optical fiber mediated flow-cell detection as well as controlling modules are installed in a suitcase with a total weight of less than 8 kg. The p-µLC is powered by DC 12V 3A or 18650 lithium battery pack and controlled by a panel computer with a custom-built windows-based chromatography workstation software for data acquisition. When using the home-made polymethacrylate based C-18 monolithic capillary column (530 µm ID×200 mm in length), the mixed alkylbenzenes can be separated and detected in an isocratic elution mode. The separation efficiency is comparable to that obtained with a commercially available HPLC.


Assuntos
Polímeros , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Indicadores e Reagentes
16.
Vet Parasitol ; 299: 109568, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34500230

RESUMO

Animal trypanosomoses due to trypanosomes of African origin (ATAO), mainly caused by Trypanosoma congolense type Savannah (TCS), T. brucei brucei (TBB), T. vivax (TV), and T. evansi, are widespread diseases that affect domestic and wild mammals and have a huge economic impact. ATAO clinical suspicions are usually confirmed by parasitological and molecular methods, while sero-epidemiological surveys are generally carried out using the OIE-recommended ELISA method based on whole cell lysate soluble antigens (WCLSA) from purified trypanosomes; this reagent is usually stored frozen. With a view to expanding this ELISA test, we assessed, standardized, and validated the use of dehydrated rather than frozen WCLSA and serum samples. For the three ELISA assays (TV, TCS & TBB), a repeatability study revealed no significant difference between repeats. The results obtained using frozen rather than freeze-dried antigen and serum strongly correlated for Pearson's correlation values (>0.93) and Lin's measure ("very good" to "excellent"). Reproducibility was robust, with Pearson's correlation values >0.97 for inter technician effects, and 0.87 (TV) to 0.97 (TBB & TCS) for inter-laboratory tests; their combination was "very satisfactory" to "excellent" according to Lin's measure and there was no impact on qualitative test results. Dehydrated reagents offer the advantage of shipment at room temperature, allowing the secured provision of reagents to regional laboratories. Together with a compendium of standard diagnostic protocols for ATAO (/OIE), dehydrated reagents will enable the serological diagnosis of ATAO at regional level in endemic countries. This very welcome improvement in the context of the Progressive Control Pathway for trypanosomes, recently launched by African countries, will possibly be extended to Latin America in the near future.


Assuntos
Trypanosoma congolense , Trypanosoma , Tripanossomíase Africana , Animais , Ensaio de Imunoadsorção Enzimática/veterinária , Indicadores e Reagentes , Mamíferos , Reprodutibilidade dos Testes , Trypanosoma vivax , Tripanossomíase Africana/diagnóstico , Tripanossomíase Africana/veterinária
17.
J Org Chem ; 86(19): 13402-13419, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34553940

RESUMO

We have prepared a library of functionalized quinolines through the magnesiation of 7-chloroquinolines under mild conditions, employing both batch and continuous flow conditions. The preparation involved the generation of mixed lithium-magnesium intermediates, which were reacted with different electrophiles. Mixed lithium-zinc reagents allowed the synthesis of halogenated and arylated derivatives. Some of the synthesized 4-carbinol quinolines have shown interesting antiproliferative properties, their hydroxyl group being a suitable amino group bioisostere. We also report a two-step approach for optically active derivatives.


Assuntos
Magnésio , Quinolinas , Indicadores e Reagentes , Lítio , Zinco
18.
J Org Chem ; 86(18): 13025-13040, 2021 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-34498466

RESUMO

N-Quaternized ketene N,O-acetals are typically an unstable, transient class of compounds most commonly observed as reactive intermediates. In this report, we describe a general synthetic approach to a variety of bench-stable N-quaternized ketene N,O-acetals via treatment of pyridine or aniline bases with acetylenic ethers and an appropriate Brønsted or Lewis acid (triflic acid, triflimide, or scandium(III) triflate). The resulting pyridinium and anilinium salts can be used as reagents or synthetic intermediates in multiple reaction types. For example, N-(1-ethoxyvinyl)pyridinium or anilinium salts can thermally release highly reactive O-ethyl ketenium ions for use in acid catalyst-free electrophilic aromatic substitutions. N-(1-Ethoxyvinyl)-2-halopyridinium salts can be employed in peptide couplings as a derivative of Mukaiyama reagents or react with amines in nucleophilic aromatic substitutions under mild conditions. These preliminary reactions illustrate the broad potential of these currently understudied compounds in organic synthesis.


Assuntos
Acetais , Cetonas , Técnicas de Química Sintética , Etilenos , Indicadores e Reagentes
19.
Front Cell Infect Microbiol ; 11: 714366, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34589443

RESUMO

Tetracycline is used as a fluorescent reagent to measure bone formation activity in bone histomorphometric analyses. However, there is a possibility to lead a different conclusion when it is used in a bacteria-infected murine model since the tetracycline is considered to work as an antibiotic reagent. There are non-antibiotic fluorescent reagents such as alizarin and calcein for measuring bone formation activity. The purpose of this study was to clarify whether tetracycline could be an appropriate reagent to measure bone formation activity in a murine bacterial model in the same way as a non-antibiotic fluorescent reagent. We used Streptococcus mutans (S. mutans), a normal inhabitant in the oral cavity and tetracycline-sensitive bacteria, for inducing the bacterial model. The murine bacterial model was generated by intravenously inoculating S. mutans to the tail vein, followed immediately by the injection of the first fluorescent reagent, and the second one was injected 2 days prior to euthanization. After one day of inoculation with S. mutans, the subcutaneously injected alizarin had a similar colony count derived from the liver and the bone marrow tissue compared to the phosphate buffered saline (PBS)-injected control group. On the other hand, subcutaneous injection of tetracycline led to a significantly lower colony count from the liver compared to alizarin- or calcein-injected group. However, on day seven, after S. mutans intravenous injections, bone mineral density of distal femurs was significantly reduced by the bacteria inoculation regardless of which fluorescent reagents were injected subcutaneously. Finally, S. mutans inoculation reduced bone-formation-activity indices in both the tetracycline-alizarin double-injected mice and the calcein-alizarin double-injected mice. These results suggested that a one-time injection of tetracycline did not affect bone formation indices in the S. mutans-induced bone loss model. Tetracycline could be used for measuring bone formation activity in the same way as non-antibiotic fluorescent reagent such as calcein and alizarin, even in a tetracycline-sensitive bacterium-infected model.


Assuntos
Osteogênese , Streptococcus mutans , Animais , Antibacterianos , Modelos Animais de Doenças , Indicadores e Reagentes , Camundongos , Tetraciclina
20.
BMC Cancer ; 21(1): 1031, 2021 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-34530761

RESUMO

BACKGROUND: Although cervical cancer is a preventable disease, screening coverage in Ethiopia is far below the target. There is limited evidence on uptake among the general population in Ethiopia. Thus, this study was conducted to assess uptake and associated factors with the cervical cancer screening "see and treat approach" among eligible women in public health facilities in Gondar town, Northwest Ethiopia. METHOD: A facility-based, cross-sectional study was conducted. The total sample size was 493. A consecutive sampling method was applied. Participants were informed about and invited to cervical cancer screening using visual inspection with acetic acid. Crude and adjusted odds ratios were calculated to determine statistical association with socio-demographic variables. Multivariable logistic regression was used to determine factors of cervical cancer screening uptake. RESULT: Out of 464 women advised for screening, 76 (16.4, 95% CI [13, 19.8%]) attended the screening. Primary education and above (AOR = 5.3, 95% CI [2.20, 13.0]), knowledge about the disease (AOR = 8.4, 95% CI [3.33, 21.21]), perceived susceptibility (AOR = 6.5, 95% CI [2.72, 15.51]), fewer perceived barriers (AOR = 6.4, 95% CI [2.30, 17.80]), cues to action (AOR = 4.6, 95% CI [1.86, 11.32]), perceived self-efficacy (AOR = 5, 95% CI [2.14, 11.73]), and previous recommendation for screening (AOR = 2.7, 95% CI [1.15, 6.51]) were significantly associated with screening uptake. CONCLUSION: The actual uptake of screening offered in this study was high relative to only 3% national screening coverage. There is a need to implement active invitation for screening with special focus on less-educated women. Repeated invitation may facilitate future screening uptake.


Assuntos
Detecção Precoce de Câncer/estatística & dados numéricos , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Avaliação de Programas e Projetos de Saúde , Neoplasias do Colo do Útero/diagnóstico , Ácido Acético , Adulto , Centros Comunitários de Saúde , Aconselhamento , Crioterapia , Técnicas de Diagnóstico Obstétrico e Ginecológico/estatística & dados numéricos , Suscetibilidade a Doenças , Escolaridade , Etiópia , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Indicadores e Reagentes , Pessoa de Meia-Idade , Autoeficácia , Neoplasias do Colo do Útero/terapia
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