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1.
Food Res Int ; 127: 108734, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31882089

RESUMO

The honeybush sensory wheel was revised, using a large sample set (n = 585) comprising of the major commercial Cyclopia species, i.e. C. intermedia, C. subternata and C. genistoides. Only positive and negative aroma attributes were included in the wheel. Chemicals were identified to serve as reference standards for the honeybush (Cyclopia spp.) lexicon. Similarly, chemical-based reference standards were identified for the rooibos (Aspalathus linearis) lexicon. From a comprehensive literature search and gas chromatography-mass spectrometry analyses, chemicals were screened by an expert panel for their suitability in terms of typicality of the target aroma. Each chemical was evaluated in a 'base tea' and compared to a specific 'reference tea' exhibiting a high intensity of the target aroma. A total of 30 and 44 chemicals for rooibos and honeybush, respectively, were selected for validation by a trained panel. Descriptive sensory analysis was conducted to assign typicality and intensity scores for each chemical representing a target aroma attribute. Several chemicals were identified as suitable reference standards for the following aroma notes: isophorone ('rooibos-woody'), maltyl isobutyrate ('caramel'), cis-3-hexenol ('green grass'), 4-oxoisophorone ('seaweed') and 2,4,6-trichloroanisole ('musty/mouldy') for rooibos; and 2-acetyl-5-methylfuran ('woody'), levulinic acid ('fynbos-sweet'), maltyl isobutyrate ('caramel'), and 2-acetylpyrrole ('nutty') for honeybush.


Assuntos
Aspalathus/química , Odorantes/análise , Adulto , Idoso , Bebidas/análise , Feminino , Humanos , Pessoa de Meia-Idade , Padrões de Referência
2.
J Chem Health Saf ; 26(2): 19-30, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31798757

RESUMO

There is a paucity of data on additive manufacturing process emissions and personal exposures in real-world workplaces. Hence, we evaluated atmospheres in four workplaces utilizing desktop "3-dimensional" (3-d) printers [fused filament fabrication (FFF) and sheer] for production, prototyping, or research. Airborne particle diameter and number concentration and total volatile organic compound concentrations were measured using real-time instruments. Airborne particles and volatile organic compounds were collected using time-integrated sampling techniques for off-line analysis. Personal exposures for metals and volatile organic compounds were measured in the breathing zone of operators. All 3-d printers that were monitored released ultrafine and fine particles and organic vapors into workplace air. Particle number-based emission rates (#/min) ranged from 9.4 × 109 to 4.4 × 1011 (n = 9samples) for FFF3-d printers and from 1.9 to 3.8 × 109 (n = 2 samples) for a sheer 3-d printer. The large variability in emission rate values reflected variability from the printers as well as differences in printer design, operating conditions, and feedstock materials among printers. A custom-built ventilated enclosure evaluated at one facility was capable of reducing particle number and total organic chemical concentrations by 99.7% and 53.2%, respectively. Carbonyl compounds were detected in room air; however, none were specifically attributed to the 3-d printing process. Personal exposure to metals (aluminum, iron) and 12 different organic chemicals were all below applicable NIOSH Recommended Exposure Limit values, but results are not reflective of all possible exposure scenarios. More research is needed to understand 3-d printer emissions, exposures, and efficacy of engineering controls in occupational settings.

3.
Saf Health Work ; 10(2): 229-236, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31297287

RESUMO

BACKGROUND: Emerging reports suggest the potential for adverse health effects from exposure to emissions from some additive manufacturing (AM) processes. There is a paucity of real-world data on emissions from AM machines in industrial workplaces and personal exposures among AM operators. METHODS: Airborne particle and organic chemical emissions and personal exposures were characterized using real-time and time-integrated sampling techniques in four manufacturing facilities using industrial-scale material extrusion and material jetting AM processes. RESULTS: Using a condensation nuclei counter, number-based particle emission rates (ERs) (number/min) from material extrusion AM machines ranged from 4.1 × 1010 (Ultem filament) to 2.2 × 1011 [acrylonitrile butadiene styrene and polycarbonate filaments). For these same machines, total volatile organic compound ERs (µg/min) ranged from 1.9 × 104 (acrylonitrile butadiene styrene and polycarbonate) to 9.4 × 104 (Ultem). For the material jetting machines, the number-based particle ER was higher when the lid was open (2.3 × 1010 number/min) than when the lid was closed (1.5-5.5 × 109 number/min); total volatile organic compound ERs were similar regardless of the lid position. Low levels of acetone, benzene, toluene, and m,p-xylene were common to both AM processes. Carbonyl compounds were detected; however, none were specifically attributed to the AM processes. Personal exposures to metals (aluminum and iron) and eight volatile organic compounds were all below National Institute for Occupational Safety and Health (NIOSH)-recommended exposure levels. CONCLUSION: Industrial-scale AM machines using thermoplastics and resins released particles and organic vapors into workplace air. More research is needed to understand factors influencing real-world industrial-scale AM process emissions and exposures.

4.
PLoS One ; 13(9): e0201341, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30231022

RESUMO

INTRODUCTION: Despite considerable progress, just over half of the 37 million people eligible to start antiretroviral therapy (ART) have accessed treatment and millions of HIV-positive people still do not know their status. With demand for ART continuing to grow, meeting the ambitious 90-90-90 HIV treatment targets will depend on improved access to high-quality diagnostics to both diagnose infection and monitor treatment adherence in low and middle-income countries (LMICs). Robust projections of future demand for CD4, viral load (VL), HIV early-infant-diagnosis (EID) tests and HIV rapid diagnostic tests (RDTs) are needed as scale-up continues. METHODS: We estimate the current coverage for HIV diagnostics and project future demand to 2021 using a consolidated forecast using data on past coverage and current demand from a number of sources, from 130 predominantly LMIC countries. RESULTS: We forecast that the overall number of CD4 tests is expected to decline between now and 2021 as more countries adopt test-and-treat and shift to VL testing for patient monitoring. Our consolidated forecast projects a gradual decline in demand for CD4 tests to 16.6 million by 2021. We anticipate that demand for VL tests will increase to 28.5 million by 2021, reflecting the increasing number of people who will receive ART and the adoption of VL testing for patient monitoring. We expect that the demand for EID tests will grow more rapidly than in past years, driven by the implementation of testing at birth in programmes globally, in line with WHO guideline recommendations, doubling to 2.1 million tests by 2021. Demand for rapid diagnostic tests is also likely to increase, reaching 509 million tests by 2021. DISCUSSION: In order to achieve the ambitious 90-90-90 targets, it will be essential to maintain and improve access to CD4, VL, EID tests and RDTs. These projections provide insight into the global demand we can expect to see for these HIV monitoring and diagnostic tests, both in relation to historical trends, and the 90-90-90 targets. Our projections will better enable producers to ensure adequate supply, and to support procurement organisations in planning future funding and purchase plans to meet the anticipated demand. The findings highlight the ongoing need for governments and international funding bodies to prioritise improving capacity and access to HIV diagnostic and monitoring technologies in line with demand.


Assuntos
Bases de Dados Factuais , Previsões , Infecções por HIV , HIV-1 , Modelos Biológicos , Antirretrovirais/uso terapêutico , Monitoramento Epidemiológico , Feminino , Infecções por HIV/diagnóstico , Infecções por HIV/tratamento farmacológico , Infecções por HIV/epidemiologia , Humanos , Masculino , Monitorização Fisiológica
5.
J Appl Microbiol ; 124(2): 598-610, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29193551

RESUMO

AIMS: To utilize a three-tiered approach to provide insight into the microbial community structure, the spatial distribution and the metabolic capabilities of organisms of a biofilm in the two towers of a high-rate biological contact reactor treating winery wastewater. METHODS AND RESULTS: Next-generation sequencing indicated that bacteria primarily responsible for the removal of carbohydrates, sugars and alcohol were more abundant in tower 1 than tower 2 while nitrifying and denitrifying bacteria were more abundant in tower 2. Yeast populations differed in each tower. Fluorescent in situ hybridization coupled with confocal microscopy showed distribution of organisms confirming an oxygen gradient across the biofilm depth. The Biolog system (ECO plates) specified the different carbon-metabolizing profiles of the two biofilms. CONCLUSIONS: The three-tiered approach confirmed that the addition of a second subunit to the bioreactor, expanded the treatment capacity by augmenting the microbial and metabolic diversity of the system, improving the treatment scope of the system. SIGNIFICANCE AND IMPACT OF THE STUDY: A three-tiered biofilm analysis provided data required to optimize the design of a bioreactor to provide favourable conditions for the development of a microbial consortium, which has optimal waste removal properties for the treatment requirements at hand.


Assuntos
Bactérias/metabolismo , Biofilmes , Resíduos Industriais/análise , Águas Residuárias/microbiologia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Biodegradação Ambiental , Reatores Biológicos/microbiologia , Carbono/metabolismo , Hibridização in Situ Fluorescente , Nitrificação , Oxigênio/metabolismo , Eliminação de Resíduos Líquidos/métodos
6.
Anaesthesia ; 72(4): 444-451, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27928821

RESUMO

The Universal Anaesthesia Machine has been developed as a complete anaesthesia workstation for use in low- and middle-income countries, where the provision of safe general anaesthesia is often compromised by unreliable supply of electricity and anaesthetic gases. We performed a functional and clinical assessment of this anaesthetic machine, with particular reference to novel features and functioning in the intended environment. The Universal Anaesthesia Machine was found to be reliable, safe and consistent across a range of tests during targeted functional testing.


Assuntos
Anestesiologia/instrumentação , Adolescente , Anestesia Geral/instrumentação , Anestésicos Inalatórios/química , Criança , Pré-Escolar , Países em Desenvolvimento , Fontes de Energia Elétrica , Falha de Equipamento , Feminino , Saúde Global , Humanos , Lactente , Masculino , Oxigênio/administração & dosagem , Pobreza , Respiração Artificial
7.
Sci Rep ; 6: 30688, 2016 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-27477963

RESUMO

The resilience of tropical corals to ocean acidification depends on their ability to regulate the pH within their calcifying fluid (pHcf). Recent work suggests pHcf homeostasis under short-term exposure to pCO2 conditions predicted for 2100, but it is still unclear if pHcf homeostasis can be maintained throughout a corals lifetime. At CO2 seeps in Papua New Guinea, massive Porites corals have grown along a natural seawater pH gradient for decades. This natural gradient, ranging from pH 8.1-7.4, provides an ideal platform to determine corals' pHcf (using boron isotopes). Porites maintained a similar pHcf (~8.24) at both a control (pH 8.1) and seep-influenced site (pH 7.9). Internal pHcf was slightly reduced (8.12) at seawater pH 7.6, and decreased to 7.94 at a site with a seawater pH of 7.4. A growth response model based on pHcf mirrors the observed distribution patterns of this species in the field. We suggest Porites has the capacity to acclimate after long-time exposure to end-of-century reduced seawater pH conditions and that strong control over pHcf represents a key mechanism to persist in future oceans. Only beyond end-of-century pCO2 conditions do they face their current physiological limit of pH homeostasis and pHcf begins to decrease.


Assuntos
Aclimatação , Antozoários/fisiologia , Dióxido de Carbono/análise , Homeostase , Água do Mar/química , Animais , Antozoários/crescimento & desenvolvimento , Concentração de Íons de Hidrogênio , Modelos Biológicos , Papua Nova Guiné
8.
Anaesthesia ; 70(9): 1101-2, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26263870
9.
PLoS One ; 10(7): e0132950, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26208351

RESUMO

The genus Cyclopia, an indigenous South African fynbos plant used to prepare honeybush tea, contains phytoestrogenic compounds. An extract from C. subternata, SM6Met, displays three desirable estrogenic attributes for future development of a phytoestrogenic nutraceutical, namely, ERα antagonism, ERß agonism, and also antagonism of E2-induced breast cancer cell proliferation. Activity-guided fractionation of SM6Met was used in an attempt to isolate and identify compounds conferring the desirable estrogenic profile to SM6Met. Initial liquid-liquid fractionation of SM6Met yielded a polar fraction (PF) and a non-polar fraction (NPF), with the desirable estrogenic attributes retained in the NPF. Subsequent high performance counter-current chromatography (HPCCC) fractionation of the NPF yielded three fractions (F1-F3). Interestingly, the fractions revealed separation of the previously demonstrated positive estrogenic attributes of the NPF into separate fractions, with F1 and F2 acting as ERα antagonists, only F2 inducing antagonism of E2-induced breast cancer cell proliferation and only F3 retaining robust ERß agonist activity. In terms of major polyphenols, quantitative HPLC and liquid chromatography tandem mass spectrometry (LC-MS/MS) indicated that HPCCC fractionation resulted in a divergence of polyphenolic classes, with F1 emerging as the dihydrochalcone-rich fraction and F2 as the flavanone- and benzophenone-rich fraction, while the xanthones, flavones and phenolic acids were retained in F3. F3 was re-engineered into F3R by reassembling the major polyphenols identified in the fraction. F3R could, however, not replicate the effect of F3. In conclusion, although activity-guided fractionation results suggest that retention of all the desirable estrogenic attributes of the original SM6Met in one fraction is not an attainable goal, fractionation is a useful tool to enhance specific desirable estrogenic attributes.


Assuntos
Fracionamento Químico/métodos , Fabaceae/química , Fitoestrógenos/isolamento & purificação , Fitoestrógenos/farmacologia , Proliferação de Células/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Suplementos Nutricionais , Avaliação Pré-Clínica de Medicamentos , Estradiol/farmacologia , Receptor alfa de Estrogênio/antagonistas & inibidores , Receptor beta de Estrogênio/agonistas , Células HEK293 , Humanos , Células MCF-7 , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Espectrometria de Massas em Tandem
10.
Oncogene ; 34(44): 5548-59, 2015 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-25703328

RESUMO

Although microRNAs (miRs) have been implicated in the pathogenesis of various human malignancies, limited information is available regarding mechanisms by which these noncoding RNAs contribute to initiation and progression of tobacco-induced esophageal cancers. In this study, array and quantitative reverse transcriptase-PCR techniques were used to examine miR expression in immortalized esophageal epithelia (IEE) and esophageal adenocarcinoma (EAC) cells cultured in normal media with or without cigarette smoke condensate (CSC). Under relevant exposure conditions, CSC significantly decreased miR-217 expression in these cells. Endogenous levels of miR-217 expression in cultured EAC cells (EACC)/primary EACs were significantly lower than those observed in IEE/ paired normal esophageal tissues. RNA crosslink immunoprecipitation, quantitative reverse transcriptase-PCR (qRT-PCR) and immunoblot experiments demonstrated direct interaction of miR-217 with kallikrein 7 (KLK7), encoding a putative oncogene not previously implicated in EAC. Repression of miR-217 correlated with increased levels of KLK7 in primary EACs, particularly those from smokers. Chromatin and methylated DNA immunoprecipitation experiments demonstrated that CSC-mediated repression of miR-217 coincided with DNMT3b-dependent hypermethylation and decreased occupancy of nuclear factor 1 within the miR-217 genomic locus. Deoxyazacytidine induced miR-217 expression and downregulated KLK7 in EACC; deoxyazacytidine also attenuated CSC-mediated miR-217 repression and upregulation of KLK7 in IEE and EACC. Overexpression of miR-217 significantly decreased, whereas overexpression of KLK7 increased proliferation, invasion and tumorigenicity of EACC. Collectively, these data demonstrate that epigenetic repression of miR-217 contributes to the pathogenesis of EAC via upregulation of KLK7 and suggest that restoration of miR-217 expression may be a novel treatment strategy for these malignancies.


Assuntos
Adenocarcinoma/genética , Carcinogênese/genética , Repressão Epigenética/genética , Neoplasias Esofágicas/genética , MicroRNAs/genética , Nicotiana/efeitos adversos , Fumar/genética , Adenocarcinoma/patologia , Carcinogênese/patologia , Linhagem Celular Tumoral , Proliferação de Células/genética , Cromatina/genética , Metilação de DNA/genética , Regulação para Baixo/genética , Neoplasias Esofágicas/patologia , Regulação Neoplásica da Expressão Gênica/genética , Humanos , Calicreínas/genética , Fatores de Transcrição NFI/genética , Invasividade Neoplásica/genética , Fumaça/efeitos adversos , Regulação para Cima/genética
11.
Geobiology ; 13(2): 170-80, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25515845

RESUMO

Microbialite-forming microbial mats in a hypersaline lake on the atoll of Kiritimati were investigated with respect to microgradients, bulk water chemistry, and microbial community composition. O2, H2S, and pH microgradients show patterns as commonly observed for phototrophic mats with cyanobacteria-dominated primary production in upper layers, an intermediate purple layer with sulfide oxidation, and anaerobic bottom layers with sulfate reduction. Ca(2+) profiles, however, measured in daylight showed an increase of Ca(2+) with depth in the oxic zone, followed by a sharp decline and low concentrations in anaerobic mat layers. In contrast, dark measurements show a constant Ca(2+) concentration throughout the entire measured depth. This is explained by an oxygen-dependent heterotrophic decomposition of Ca(2+)-binding exopolymers. Strikingly, the daylight maximum in Ca(2+) and subsequent drop coincides with a major zone of aragonite and gypsum precipitation at the transition from the cyanobacterial layer to the purple sulfur bacterial layer. Therefore, we suggest that Ca(2+) binding exopolymers function as Ca(2+) shuttle by their passive downward transport through compression, triggering aragonite precipitation in the mats upon their aerobic microbial decomposition and secondary Ca(2+) release. This precipitation is mediated by phototrophic sulfide oxidizers whose action additionally leads to the precipitation of part of the available Ca(2+) as gypsum.


Assuntos
Biota , Cálcio/análise , Sedimentos Geológicos/química , Sedimentos Geológicos/microbiologia , Biopolímeros/metabolismo , Chromatiaceae/isolamento & purificação , Chromatiaceae/metabolismo , Cianobactérias/isolamento & purificação , Cianobactérias/metabolismo , Sulfeto de Hidrogênio/análise , Concentração de Íons de Hidrogênio , Micronésia , Oxigênio/análise , Oceano Pacífico
12.
Talanta ; 115: 590-9, 2013 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-24054637

RESUMO

A nested analysis of variance combined with simultaneous component analysis, ASCA, was proposed to model high-dimensional chromatographic data. The data were obtained from an experiment designed to investigate the effect of production season, quality grade and post-production processing (steam pasteurization) on the phenolic content of the infusion of the popular herbal tea, rooibos, at 'cup-of-tea' strength. Specifically, a four-way analysis of variance where the experimental design involves nesting in two of the three crossed factors was considered. For the purpose of the study, batches of fermented rooibos plant material were sampled from each of four quality grades during three production seasons (2009, 2010 and 2011) and a sub-sample of each batch was steam-pasteurized. The phenolic content of each rooibos infusion was characterized by high performance liquid chromatography (HPLC)-diode array detection (DAD). In contrast to previous studies, the complete HPLC-DAD signals were used in the chemometric analysis in order to take into account the entire phenolic profile. All factors had a significant effect on the phenolic content of a 'cup-of-tea' strength rooibos infusion. In particular, infusions prepared from the grade A (highest quality) samples contained a higher content of almost all phenolic compounds than the lower quality plant material. The variations of the content of isoorientin and orientin in the different quality grade infusions over production seasons are larger than the variations in the content of aspalathin and quercetin-3-O-robinobioside. Ferulic acid can be used as an indicator of the quality of rooibos tea as its content generally decreases with increasing tea quality. Steam pasteurization decreased the content of the majority of phenolic compounds in a 'cup-of-tea' strength rooibos infusion.


Assuntos
Aspalathus/química , Bebidas/análise , Chalconas/análise , Ácidos Cumáricos/análise , Flavonoides/análise , Glucosídeos/análise , Fenóis/análise , Folhas de Planta/química , Análise de Variância , Cromatografia Líquida de Alta Pressão , Fermentação , Pasteurização , Análise de Componente Principal , Estações do Ano , Vapor
13.
Phytomedicine ; 20(10): 813-9, 2013 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-23639187

RESUMO

Increased levels of free fatty acids (FFAs), specifically saturated free fatty acids such as palmitate are associated with insulin resistance of muscle, fat and liver. Skeletal muscle, responsible for up to 80% of the glucose disposal from the peripheral circulation, is particularly vulnerable to increased levels of saturated FFAs. Rooibos (Aspalathus linearis) and its unique dihydrochalcone C-glucoside, aspalathin, shown to reduce hyperglycemia in diabetic rats, could play a role in preventing or ameliorating the development of insulin resistance. This study aims to establish whether rooibos can ameliorate experimentally-induced insulin-resistance in C2C12 skeletal muscle cells. Palmitate-induced insulin resistant C2C12 cells were treated with an aspalathin-enriched green (unfermented) rooibos extract (GRE), previously shown for its blood glucose lowering effect in vitro and in vivo or an aqueous extract of fermented rooibos (FRE). Glucose uptake and mitochondrial activity were measured using 2-deoxy-[³H]-D-glucose, MTT and ATP assays, respectively. Expression of proteins relevant to glucose metabolism was analysed by Western blot. GRE contained higher levels of all compounds, except the enolic phenylpyruvic acid-2-O-glucoside and luteolin-7-O-glucoside. Both rooibos extracts increased glucose uptake, mitochondrial activity and ATP production. Compared to FRE, GRE was more effective at increasing glucose uptake and ATP production. At a mechanistic level both extracts down-regulated PKC θ activation, which is associated with palmitate-induced insulin resistance. Furthermore, the extracts increased activation of key regulatory proteins (AKT and AMPK) involved in insulin-dependent and non-insulin regulated signalling pathways. Protein levels of the glucose transporter (GLUT4) involved in glucose transport via these two pathways were also increased. This in vitro study therefore confirms that rooibos can ameliorate palmitate-induced insulin resistance in C2C12 skeletal muscle cells. Inhibition of PKC θ activation and increased activation of AMPK and AKT offer a plausible mechanistic explanation for this ameliorative effect.


Assuntos
Aspalathus , Resistência à Insulina/fisiologia , Músculo Esquelético/citologia , Músculo Esquelético/efeitos dos fármacos , Ácido Palmítico/uso terapêutico , Fitoterapia , Extratos Vegetais/uso terapêutico , Animais , Aspalathus/química , Linhagem Celular , Hiperinsulinismo/induzido quimicamente , Hiperinsulinismo/tratamento farmacológico , Camundongos , Músculo Esquelético/enzimologia , Ácido Palmítico/farmacologia , Extratos Vegetais/farmacologia
14.
Phytomedicine ; 20(1): 32-9, 2012 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-23083813

RESUMO

Rooibos, an endemic South African plant, known for its use as herbal tea, has potential as an antidiabetic herbal product, following recent demonstration of the glucose lowering effect of its major flavonoid, the dihydrochalcone C-glucoside aspalathin. The purpose of this study was to confirm antidiabetic activity for rooibos extract high in aspalathin content. An extract (SB1) was selected after screening for high aspalathin content and α-glucosidase inhibition activity. On-line HPLC-biochemical detection confirmed α-glucosidase inhibitory activity for aspalathin. In vitro the extract induced a dose response increase in glucose uptake (5 × 10⁻5 to 5 µg/ml) on C2C12 myotubules. Aspalathin was effective at 1, 10 and 100 µM, while rutin was effective at 100 µM. In the Chang cells only the extract was effective. In vivo the extract sustained a glucose lowering effect comparable to metformin over a 6h period after administration (25mg/kg body weight (BW)) to STZ-induced diabetic rats. In an oral glucose tolerance test the extract (30 mg/kg BW) was more effective than vildagliptin (10mg/kg BW), a dipeptidyl peptidase-4 inhibitor. An aspalathin-rutin mixture (1:1; m/m) dosed at 1.4 mg/kg BW, but not the single compounds separately, reduced blood glucose concentrations of STZ-induced diabetic rats over a 6h monitoring period. The improved hypoglycemic activity of the aspalathin-rutin mixture and the extract illustrated synergistic interactions of polyphenols in complex mixtures.


Assuntos
Aspalathus/química , Glicemia/metabolismo , Chalconas/uso terapêutico , Diabetes Mellitus Experimental/tratamento farmacológico , Hipoglicemiantes/uso terapêutico , Fitoterapia , Extratos Vegetais/uso terapêutico , Adamantano/análogos & derivados , Adamantano/farmacologia , Animais , Linhagem Celular , Chalconas/farmacologia , Diabetes Mellitus Experimental/sangue , Inibidores da Dipeptidil Peptidase IV/farmacologia , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Teste de Tolerância a Glucose , Inibidores de Glicosídeo Hidrolases , Hipoglicemiantes/farmacologia , Masculino , Nitrilas/farmacologia , Extratos Vegetais/farmacologia , Pirrolidinas/farmacologia , Ratos , Ratos Wistar , Rutina/farmacologia , Rutina/uso terapêutico , Vildagliptina
15.
Phytomedicine ; 19(8-9): 730-6, 2012 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-22516895

RESUMO

Athrixia phylicoides DC. is an aromatic shrub indigenous to the eastern parts of Southern Africa. Indigenous communities brew "bush tea" from dried twigs and leaves of A. phylicoides, which is consumed as a beverage and used for its medicinal properties. Plant polyphenols have been shown to be beneficial to Type 2 diabetes mellitus (T2D) and obesity. Aqueous extracts of the plant have been shown to be rich in polyphenols, in particular phenolic acids, which may enhance glucose uptake and metabolism. The aim of this study was to determine the phenolic composition of a hot water A. phylicoides extract and assess its in vitro effect on cellular glucose utilisation. The most abundant phenolic compounds in the extract were 6-hydroxyluteolin-7-O-glucoside, chlorogenic acid, protocatechuic acid, a di-caffeoylquinic acid and a methoxy-flavonol derivative. The extract increased glucose uptake in C2C12, Chang and 3T3-L1 cells, respectively. Intracellular glucose was utilised by both oxidation (C2C12 myocytes and Chang cells; p < 0.01 and p < 0.05, respectively) and by increased glycogen storage (Chang cells; p < 0.05). No cytotoxicity was observed in Chang cells at the concentrations tested. The effects of the extract were not dose-dependent. A. phylicoides aqueous extract stimulated in vitro glucose uptake and metabolism, suggesting that consumption of this phenolic-rich extract could potentially ameliorate metabolic disorders related to obesity and T2D.


Assuntos
Asteraceae/química , Glucose/metabolismo , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Células 3T3-L1/efeitos dos fármacos , África Austral , Animais , Ácido Clorogênico/análise , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Glucose/farmacocinética , Glicogênio/metabolismo , Hidroxibenzoatos/análise , Luteolina/análise , Camundongos , Fenóis/análise , Fenóis/química , Plantas Medicinais/química , Ácido Quínico/análogos & derivados
16.
Geobiology ; 9(4): 330-48, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21535364

RESUMO

Sulfidic muds of cold seeps on the Nile Deep Sea Fan (NDSF) are populated by different types of mat-forming sulfide-oxidizing bacteria. The predominant sulfide oxidizers of three different mats were identified by microscopic and phylogenetic analyses as (i) Arcobacter species producing cotton-ball-like sulfur precipitates, (ii) large filamentous sulfur bacteria including Beggiatoa species, and (iii) single, spherical Thiomargarita species. High resolution in situ microprofiles revealed different geochemical settings selecting for the different mat types. Arcobacter mats occurred where oxygen and sulfide overlapped above the seafloor in the bottom water interface. Filamentous sulfide oxidizers were associated with steep gradients of oxygen and sulfide in the sediment. A dense population of Thiomargarita was favored by temporarily changing supplies of oxygen and sulfide in the bottom water. These results indicate that the decisive factors in selecting for different mat-forming bacteria within one deep-sea province are spatial or temporal variations in energy supply. Furthermore, the occurrence of Arcobacter spp.-related 16S rRNA genes in the sediments below all three types of mats, as well as on top of brine lakes of the NDSF, indicates that this group of sulfide oxidizers can switch between different life modes depending on the geobiochemical habitat setting.


Assuntos
Arcobacter/metabolismo , Beggiatoa/metabolismo , Ecossistema , Sulfetos/metabolismo , Microbiologia da Água , Temperatura Baixa , Mar Mediterrâneo , Nitratos/metabolismo , Oxirredução
17.
Oncogene ; 30(33): 3585-98, 2011 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-21423218

RESUMO

A prominent feature of most cancers including Barrett's adenocarcinoma (BAC) is genetic instability, which is associated with development and progression of disease. In this study, we investigated the role of recombinase (hsRAD51), a key component of homologous recombination (HR)/repair, in evolving genomic changes and growth of BAC cells. We show that the expression of RAD51 is elevated in BAC cell lines and tissue specimens, relative to normal cells. HR activity is also elevated and significantly correlates with RAD51 expression in BAC cells. The suppression of RAD51 expression, by short hairpin RNA (shRNA) specifically targeting this gene, significantly prevented BAC cells from acquiring genomic changes to either copy number or heterozygosity (P<0.02) in several independent experiments employing single-nucleotide polymorphism arrays. The reduction in copy-number changes, following shRNA treatment, was confirmed by Comparative Genome Hybridization analyses of the same DNA samples. Moreover, the chromosomal distributions of mutations correlated strongly with frequencies and locations of Alu interspersed repetitive elements on individual chromosomes. We conclude that the hsRAD51 protein level is systematically elevated in BAC, contributes significantly to genomic evolution during serial propagation of these cells and correlates with disease progression. Alu sequences may serve as substrates for elevated HR during cell proliferation in vitro, as they have been reported to do during the evolution of species, and thus may provide additional targets for prevention or treatment of this disease.


Assuntos
Adenocarcinoma/genética , Elementos Alu , Esôfago de Barrett/genética , Neoplasias Esofágicas/genética , Genoma Humano , Rad51 Recombinase/fisiologia , Recombinação Genética , Linhagem Celular Tumoral , Humanos , Perda de Heterozigosidade , Mutação
18.
Int J Tuberc Lung Dis ; 14(9): 1097-103, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20819253

RESUMO

OBJECTIVE: To explore grant and country characteristics associated with the performance of tuberculosis (TB) grants supported by the Global Fund to Fight AIDS, Tuberculosis and Malaria (Global Fund), which uses performance-based funding of grants. METHODS: We used Global Fund grant data to compute the average programmatic performance of 108 TB grants in 88 countries. Using stepwise regression models, we examined the correlation of grant performance with a range of grant and country characteristics. RESULTS: Funding duration and funding per estimated smear-positive TB case were positively correlated with grant performance (partial correlations of 0.386-0.416 for the former, 0.200 for the latter). Successful completion of an evaluation of a grant during the second year of funding was linked to higher performance (0.357). Performance was further influenced by the independent organisation hired by the Global Fund to provide ongoing monitoring of the grants (0.197-0.243). Two country-specific factors were significantly correlated with performance: political stability (0.197-0.234) and disease burden (-0.211). DISCUSSION: Successful evaluation that leads to continued funding predicts higher performance of TB grants, even in challenging settings such as weak health services. However, other contextual factors affect grant performance and should be considered when assessing grants to ensure that countries that have a high disease burden and are politically unstable are not penalized.


Assuntos
Organização do Financiamento/organização & administração , Saúde Global , Tuberculose/economia , Humanos , Política , Análise de Regressão , Tuberculose/prevenção & controle , Tuberculose/terapia
19.
Environ Microbiol ; 12(9): 2466-78, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20406295

RESUMO

'Candidatus Magnetobacterium bavaricum' is unusual among magnetotactic bacteria (MTB) in terms of cell size (8-10 µm long, 1.5-2 µm in diameter), cell architecture, magnetotactic behaviour and its distinct phylogenetic position in the deep-branching Nitrospira phylum. In the present study, improved magnetic enrichment techniques permitted high-resolution scanning electron microscopy and energy dispersive X-ray analysis, which revealed the intracellular organization of the magnetosome chains. Sulfur globule accumulation in the cytoplasm point towards a sulfur-oxidizing metabolism of 'Candidatus M. bavaricum'. Detailed analysis of 'Candidatus M. bavaricum' microhabitats revealed more complex distribution patterns than previously reported, with cells predominantly found in low oxygen concentration. No correlation to other geochemical parameters could be observed. In addition, the analysis of a metagenomic fosmid library revealed a 34 kb genomic fragment, which contains 33 genes, among them the complete rRNA gene operon of 'Candidatus M. bavaricum' as well as a gene encoding a putative type IV RubisCO large subunit.


Assuntos
Bactérias/classificação , Metagenômica , Filogenia , Sequência de Aminoácidos , Bactérias/genética , Bactérias/ultraestrutura , DNA Bacteriano/genética , Ecologia , Sedimentos Geológicos/microbiologia , Dados de Sequência Molecular , RNA Ribossômico 16S/genética , Ribulose-Bifosfato Carboxilase/genética , Análise de Sequência de DNA , Microbiologia da Água
20.
J Ethnopharmacol ; 119(3): 376-412, 2008 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-18621121

RESUMO

Rooibos (Aspalathus linearis (Brum.f) Dahlg.) and honeybush (Cyclopia Vent. species) are popular indigenous South African herbal teas enjoyed for their taste and aroma. Traditional medicinal uses of rooibos in South Africa include alleviation of infantile colic, allergies, asthma and dermatological problems, while a decoction of honeybush was used as a restorative and as an expectorant in chronic catarrh and pulmonary tuberculosis. Traditional medicinal uses of Athrixia phylicoides DC., or bush tea, another indigenous South African plant with very limited localised use as herbal tea, include treatment of boils, acne, infected wounds and infected throats. Currently rooibos and honeybush are produced for the herbal tea market, while bush tea has potential for commercialisation. A summary of the historical and modern uses, botany, distribution, industry and chemical composition of these herbal teas is presented. A comprehensive discussion of in vitro, ex vivo and in vivo biological properties, required to expand their applications as nutraceutical and cosmeceutical products, is included, with the main emphasis on rooibos. Future research needs include more comprehensive chemical characterisation of extracts, identification of marker compounds for extract standardisation and quality control, bioavailability and identification of bio-markers of dietary exposure, investigation of possible herb-drug interactions and plant improvement with regards to composition and bioactivity.


Assuntos
Aspalathus/química , Asteraceae/química , Fabaceae/química , Plantas Medicinais/química , Agricultura , Animais , Asteraceae/classificação , Etnobotânica , Fabaceae/classificação , Geografia , História do Século XX , Humanos , Fitoterapia/história , Extratos Vegetais/uso terapêutico , Plantas Medicinais/efeitos adversos , Plantas Medicinais/toxicidade , África do Sul
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