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1.
Emerg Infect Dis ; 28(3): 684-692, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35202526

RESUMO

We evaluated the effects of the coronavirus disease pandemic on diagnosis of and treatment for tuberculosis (TB) in Vietnam. We obtained quarterly notifications for TB and multidrug-resistant/rifampin-resistant (MDR/RR) TB from 2015-2020 and evaluated changes in monthly TB case notifications. We used an interrupted time series to assess the change in notifications and treatment outcomes. Overall, TB case notifications were 8% lower in 2020 than in 2019; MDR/RR TB notifications were 1% lower. TB case notifications decreased by 364 (95% CI -1,236 to 508) notifications per quarter and MDR/RR TB by 1 (95% CI -129 to 132) notification per quarter. The proportion of successful TB treatment outcomes decreased by 0.1% per quarter (95% CI -1.1% to 0.8%) in 2020 compared with previous years. Our study suggests that Vietnam was able to maintain its TB response in 2020, despite the pandemic.


Assuntos
COVID-19 , Tuberculose Resistente a Múltiplos Medicamentos , Tuberculose , Antituberculosos/uso terapêutico , COVID-19/epidemiologia , Humanos , Pandemias , Estudos Retrospectivos , SARS-CoV-2 , Tuberculose/diagnóstico , Tuberculose/tratamento farmacológico , Tuberculose/epidemiologia , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Tuberculose Resistente a Múltiplos Medicamentos/epidemiologia , Vietnã/epidemiologia
2.
Biosci Biotechnol Biochem ; 86(12): 1615-1622, 2022 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-36222757

RESUMO

ß-sitosterol derived from Clinacanthus nutans Lindau was tested for its in vitro osteogenic activity using MC3T3-E1 pre-osteoblasts. Our results indicated that ß-sitosterol was non-toxic to the cells cultured at a concentration <20 µg/mL. Treatment of the cells with ß-sitosterol significantly enhanced the alkaline phosphatase activity up to 210 and 204.6% at 5 and 10 µg/mL, respectively (P < .05). Similarly, the mineralization activity of the ß-sitosterol treated cells was elevated up to 134, 168, 118% at a concentration of 2.5, 5, and 10 µg/mL, respectively (P < .05). In addition, this compound up-regulated several marker genes for osteoblast differentiation, including runx2, osx and col I to 2, 2.5 and 5.6 folds at 10 µg/mL, respectively (P < .05). The expression of p38 and ERK proteins involved in the MAPK signal pathway related to mineralization and differentiation was also enhanced. Thus, the osteoblastogenic activity of ß-sitosterol was fully illustrated for the first time.


Assuntos
Osteoblastos , Osteogênese , Regulação para Cima , Diferenciação Celular , Osteoblastos/metabolismo
3.
Z Naturforsch C J Biosci ; 70(11-12): 313-8, 2015 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-26618571

RESUMO

This study was carried out to further examine the anti-biofilm activity of α-mangostin (αMG) isolated from Garcinia mangostana L. grown in Vietnam, against a strongly biofilm producing Streptococcus mutans, a major causative agent of dental caries. The obtained data indicated that topical applications (twice-daily, 60 s exposure each) of 150 µM αMG during biofilm formation on the surfaces of hydroxyapatite disks (sHA) by S. mutans UA159 resulted in 30.7% reduction in biofilm accumulation after 68 h of growth. The treatment did not affect the viability of S. mutans cells in the biofilms. The surface activities of two key enzymes responsible for biofilm formation, i.e. the glycosyltransferases GtfB and GtfC, were reduced by 20 and 35%, respectively (vs. vehicle control, P < 0.05). Interestingly, αMG specifically targeted S. mutans in mixed biofilms, resulting in the decrease of the S. mutans population and total biofilm biomass. αMG was also found to accumulate within the biofilm of S. mutans up to 4.5 µg/biofilm, equal to a concentration of >10 µM/biofilm. In conclusion, this study confirmed anti-biofilm activity of αMG against S. mutans. A brief exposure to αMG may suppress biofilm formation by targeting key enzymes imvolved in biofilm formation.

4.
Langmuir ; 29(9): 2927-34, 2013 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-23398281

RESUMO

We present a simulation study of argon adsorption in a closed-end mesopore of uniform diameter in order to investigate the occurrence of hysteresis and propose two principal reasons for its existence: the variation in the shape and radius of curvature of the meniscus and the change in the packing of adsorbate during adsorption and desorption. This interpretation differs from classical theories that neglect both of these factors, and therefore find that adsorption-desorption in a closed-end pore is reversible. A detailed simulation study of the effects of temperature on the microscopic behavior of the adsorbate supports the interpretation proposed here.

5.
Can J Microbiol ; 57(3): 217-25, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21358763

RESUMO

The increasing prevalence of dental caries is making it more of a major world health problem. Caries is the direct result of acid production by cariogenic oral bacteria, especially Streptococcus mutans. New and better antimicrobial agents active against cariogenic bacteria are badly needed, especially natural agents derived directly from plants. We have evaluated the inhibitory actions of α-mangostin, a xanthone purified from ethanolic extracts of the tropical plant Garcinia mangostana L., by repeated silica gel chromatography. α-Mangostin was found to be a potent inhibitor of acid production by S. mutans UA159, active against membrane enzymes, including the F(H+)-ATPase and the phosphoenolpyruvate - sugar phosphotransferase system. α-Mangostin also inhibited the glycolytic enzymes aldolase, glyceraldehyde-3-phosphate dehydrogenase, and lactic dehydrogenase. Glycolysis by intact cells in suspensions or biofilms was inhibited by α-mangostin at concentrations of 12 and 120 µmol·L⁻¹, respectively, in a pH-dependent manner, with greater potency at lower pH values. Other targets for inhibition by α-mangostin included (i) malolactic fermentation, involved in alkali production from malate, and (ii) NADH oxidase, the major respiratory enzyme for S. mutans. The overall conclusion is that α-mangostin is a multitarget inhibitor of mutans streptococci and may be useful as an anticaries agent.


Assuntos
Antibacterianos/farmacologia , Extratos Vegetais/farmacologia , Streptococcus mutans/efeitos dos fármacos , Xantonas/farmacologia , Álcalis/metabolismo , Biofilmes/efeitos dos fármacos , Fermentação , Garcinia mangostana/química , Glicólise , Malatos/metabolismo , Oxigênio/metabolismo , Sistema Fosfotransferase de Açúcar do Fosfoenolpiruvato/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , ATPases Translocadoras de Prótons/antagonistas & inibidores , Streptococcus mutans/enzimologia
6.
Saudi J Biol Sci ; 28(3): 1615-1621, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33732047

RESUMO

This study aimed to investigate the antibiofilm activity of alpha-mangostin (AMG) loaded nanoparticles (nanoAMG) against Staphylococcus aureus, including the methicillin-resistant strain MRSA252. The results indicated that treatment with 24 µmol/L nanoAMG inhibited the formation of biofilm biomass by 53-62%, compared to 40-44% for free AMG (p < 0.05). At 48 µmol/L, biofilms in all nanoAMG treated samples were nearly fully disrupted for the two tested strains, MRSA252 and the methicillin-sensitive strain NCTC6571. That concentration resulted in killing of biofilm cells. A lower concentration of 12 µmol/L nanoAMG inhibited initial adherence of the two bacterial strains by > 50%. In contrast, activity of nanoAMG was limited on preformed mature biofilms, which at a concentration of 48 µmol/L were reduced only by 27% and 22% for NCTC6571 and MRSA252, respectively. The effects of AMG or nanoAMG on the expression of biofilm-related genes showed some noticeable differences between the two strains. For instance, the expression level of ebpS was downregulated in MRSA252 and upregulated in NCTC6571 when those strains were treated with either AMG or nanoAMG. In contrast, the expression of fnbB was down regulated in NCTC6571, while it was up-regulated in the MRSA252. The expression of other biofilm-related genes (icaC, clfB and fnbA) was down regulated in both strains. In conclusion, our results suggest that AMG coated nanoparticles had enhanced biological activity as compared to free AMG, indicating that nanoAMG could be a new and promising inhibitor of biofilm formation to tackle S. aureus, including strains that are resistant to multiple antibiotics.

7.
Foods ; 10(2)2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-33498449

RESUMO

When wheat experiences a cold-temperature 'shock' during the late stage of grain filling, it triggers the abnormal synthesis of late-maturity α-amylase (LMA). This increases the enzyme content in affected grain, which can lead to a drastic reduction in falling number (FN). By commercial standards, a low FN is taken as an indication of inferior quality, deemed unsuitable for end-product usage. Hence, LMA-affected grains are either rejected or downgraded to feed grade at the grain receiving point. However, previous studies have found no substantial correlation between low FN-LMA and bread quality. The present study extends previous investigations to semi-solid food, evaluating the physical quality of fresh white sauce processed from LMA-affected flour. Results show that high-LMA flours had low FNs and exhibited poor pasting characteristics. However, gelation occurred in the presence of other components during fresh white sauce processing. This demonstrates that LMA-affected flours may have new applications in low-viscosity products.

8.
BMC Complement Med Ther ; 21(1): 231, 2021 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-34517853

RESUMO

BACKGROUND: Neorautanenia mitis, Hydnora abyssinica, and Senna surattensis are medicinal plants with a variety of traditional uses. In this study, we sought to isolate the bioactive compounds responsible for some of these activities, and to uncover their other potential medicinal properties. METHODS: The DCM and ethanol extracts of the roots of N. mitis and H. abyssinica, and the leaves of S. surattensis were prepared and their phytochemical components were isolated and purified using chromatographic methods. These extracts and their pure phytochemical components were evaluated in in-vitro models for their inhibitory activities against Plasmodium falciparum, Trypanosoma brucei rhodesiense, Mycobacterium tuberculosis, α-amylase (AA), and α-glucosidase (AG). RESULTS: Rautandiol B had significant inhibitory activities against two strains of Plasmodium falciparum showing a high safety ratio (SR) and IC50 values of 0.40 ± 0.07 µM (SR - 108) and 0.74 ± 0.29 µM (SR - 133) against TM4/8.2 and K1CB1, respectively. While (-)-2-isopentenyl-3-hydroxy-8-9-methylenedioxypterocarpan showed the highest inhibitory activity against T. brucei rhodesiense with an IC50 value of 4.87 ± 0.49 µM (SR > 5.83). All crude extracts showed inhibitory activities against AA and AG, with three of the most active phytochemical components; rautandiol A, catechin, and dolineon, having only modest activities against AG with IC50 values of 0.28 mM, 0.36 mM and 0.66 mM, respectively. CONCLUSION: These studies have led to the identification of lead compounds with potential for future drug development, including Rautandiol B, as a potential lead compound against Plasmodium falciparum. The relatively higher inhibitory activities of the crude extracts against AG and AA over their isolated components could be due to the synergistic effects between their phytochemical components. These crude extracts could potentially serve as alternative inhibitors of AG and AA and as therapeutics for diabetes.


Assuntos
Antimaláricos/farmacologia , Antimaláricos/uso terapêutico , Fabaceae/química , Malária Falciparum/tratamento farmacológico , Pterocarpanos/farmacologia , Pterocarpanos/uso terapêutico , Senna/química , Humanos , Medicina Tradicional/métodos , Medicina Tradicional/estatística & dados numéricos , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêutico , Folhas de Planta/química , Raízes de Plantas/química , Plantas Medicinais/química , Plasmodium falciparum/efeitos dos fármacos
9.
Can J Microbiol ; 56(7): 539-47, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20651853

RESUMO

Alkali production by oral streptococci is considered important for dental plaque ecology and caries moderation. Recently, malolactic fermentation (MLF) was identified as a major system for alkali production by oral streptococci, including Streptococcus mutans. Our major objectives in the work described in this paper were to further define the physiology and genetics of MLF of oral streptococci and its roles in protection against metabolic stress damage. L-Malic acid was rapidly fermented to L-lactic acid and CO(2) by induced cells of wild-type S. mutans, but not by deletion mutants for mleS (malolactic enzyme) or mleP (malate permease). Mutants for mleR (the contiguous regulator gene) had intermediate capacities for MLF. Loss of capacity to catalyze MLF resulted in loss of capacity for protection against lethal acidification. MLF was also found to be protective against oxidative and starvation damage. The capacity of S. mutans to produce alkali from malate was greater than its capacity to produce acid from glycolysis at low pH values of 4 or 5. MLF acted additively with the arginine deiminase system for alkali production by Streptococcus sanguinis, but not with urease of Streptococcus salivarius. Malolactic fermentation is clearly a major process for alkali generation by oral streptococci and for protection against environmental stresses.


Assuntos
Ácidos/farmacologia , Álcalis/metabolismo , Fermentação , Malatos/metabolismo , Boca/microbiologia , Estresse Oxidativo , Streptococcus/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Malato Desidrogenase/genética , Malato Desidrogenase/metabolismo , Streptococcus/efeitos dos fármacos , Streptococcus/genética
10.
Z Naturforsch C J Biosci ; 75(5-6): 145-151, 2020 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-32286252

RESUMO

The compound α-mangostin (AMG) extracted from Garcinia mangostana L. has potent anticancer properties but its clinical application is limited because of its poor solubility. In this study, AMG-loaded nanoparticles (NMG) were synthesized using a new formula and their apoptosis activity against human cervical carcinoma (HeLa) cells was investigated in comparison with organic solvent-soluble AMG in free form. The NMG was successfully synthesized with a particle size of <50 nm, polydispersity index <0.3, and zeta potential of -35.2 mV. At a concentration of 10 µg/mL, AMG reduced cell survival by 60%, whereas NMG treatment resulted in >90% cell death (p < 0.05). The AMG- or NMG-treated cells also showed changes in the size and shape and exhibited enhanced intensity of blue-stained nuclei, as well as decreased cell density, especially in NMG-treated cells. After 24 h of incubation with AMG or NMG, the cells went through late apoptosis at a rate of approximately 34% in 20 µg/mL AMG treatment and 27% in 10 µg/mL NMG treatment (p < 0.05). Thus, HeLa cells underwent more pronounced cell death through apoptosis induction caused by the NMG treatment compared to that caused by AMG. Clearly, the new NMG improved AMG bioavailability while maintaining the desired activity.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Garcinia mangostana/química , Inibidores de Proteínas Quinases/farmacologia , Neoplasias do Colo do Útero/enzimologia , Xantonas/farmacologia , Antineoplásicos Fitogênicos/química , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Composição de Medicamentos , Feminino , Células HeLa , Humanos , Nanopartículas , Tamanho da Partícula , Inibidores de Proteínas Quinases/química , Neoplasias do Colo do Útero/tratamento farmacológico , Xantonas/química
11.
Nat Prod Res ; 34(17): 2518-2523, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30600706

RESUMO

Rhodomyrtone was isolated from the leaves of Rhodomyrtus tomentosa (Aiton) Hassk grown in Vietnam using chromatographic methods. Its chemical structure was confirmed by means of spectroscopic data analysis. The pH drop measurement, enzyme activity assays and fluorescence stain were used to examine rhodomyrtone anticaries activity. It was found that rhodomyrtone suppressed acid production by Streptococcus mutans, a major cariogenic agent in human by inhibiting enzyme activities responsible for acid production and tolerance, including membrane bound enzymes F-ATPase and phosphotransferase system (PTS), as well as glycolysis enzymes glyceraldehyphosphate dehydrogenase (GAPDH) and pyruvate kinase (PK) in cytoplasm with the IC50 values of 24 µM, 19 µM, 23 µM and 28 µM, respectively. Moreover, 50 µM rhodomyrtone reduced biofilm biomass formed by S. mutans up to 59% (p < 0.05). Fluorescent images indicated that cells on the biofilms were significantly killed. Thus, rhodomyrtone is a new and potential anticaries agent against S. mutans.


Assuntos
Antibacterianos/isolamento & purificação , Cariostáticos/isolamento & purificação , Myrtaceae/química , Xantonas/isolamento & purificação , Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Cariostáticos/farmacologia , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Extratos Vegetais/química , Folhas de Planta/química , Streptococcus mutans/efeitos dos fármacos , Streptococcus mutans/enzimologia , Vietnã , Xantonas/farmacologia
12.
J Texture Stud ; 49(3): 274-285, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29058322

RESUMO

Effects of adding four functional ingredients: inulin, pectin, galacto-oligosaccharides (GOS), and beta glucan on physical, rheology, tribology, and sensory characteristics of skim (0.1% fat) stirred yoghurt were studied. Three levels of each ingredient were chosen: inulin (7, 8, and 9%), pectin (0.2, 0.25, and 0.3%), GOS (9.1, 11.3, and 13.6%), and beta glucan (0.1, 0.2, and 0.3%). Among the investigated ingredients, inulin and GOS appeared to be preferable choices due to their ability to both reduce syneresis and slightly increase sample lubrication while maintaining texture, rheology, and sensory characteristics of skim yoghurt. Pectin and beta glucan, conversely, increased viscosity and gel strength, slightly increased sample lubrication for the skim yoghurt but created large particles (i.e., greater than 100 µm) in the product body. This led to the increase in lumpiness and residual coating while reducing smoothness and creaminess of the sample. The observed tribology behaviors of the stirred yoghurts were similar to the previous study of pot-set yoghurt whose friction curves comprised four friction zones (Nguyen, Kravchuk, Bhandari, and Prakash). The sensory characteristics of six selected samples for various texture and mouthfeel attributes obtained from a trained panel were in agreement with particle size, rheology, and tribology characteristics of the yoghurt samples. PRACTICAL APPLICATIONS: With the increasing demand for low fat and functional food, there is a need to understand the impact of adding functional ingredients in low fat yoghurt to satisfy consumers' requirements. This study investigates the effects of these functional ingredients at different dosages on physical, rheology, tribology, and sensory characteristics of skim (0.1% fat) stirred yoghurt. The results from this study may guide use of functional ingredients in yoghurt production.


Assuntos
Aditivos Alimentares/análise , Tecnologia de Alimentos , Iogurte/análise , Cor , Humanos , Inulina/administração & dosagem , Oligossacarídeos/análise , Pectinas/análise , Reologia , Viscosidade , beta-Glucanas/análise
13.
FEMS Microbiol Lett ; 254(1): 134-40, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16451191

RESUMO

Fluoride and zinc, alone or in combination at concentrations of 0.2 mM, inhibited production-secretion of glucosyltranferases by Streptococcus mutans UA159 growing in suspension cultures. Inhibition did not involve growth inhibition or starvation. Fluoride and zinc also inhibited glucan production, especially insoluble glucan, in fed-batch biofilms. Inhibition of biofilms appeared to be associated with starvation as indicated by markedly decreased ATP pools and iodophilic polysaccharide levels in biofilm cells. As insoluble glucans are important for virulence of mutans streptococci, the inhibitory actions of fluoride and zinc could significantly affect cariogenicity.


Assuntos
Glucosiltransferases/antagonistas & inibidores , Polissacarídeos Bacterianos/biossíntese , Fluoreto de Sódio/farmacologia , Streptococcus mutans/efeitos dos fármacos , Streptococcus mutans/crescimento & desenvolvimento , Sulfato de Zinco/farmacologia , Biofilmes/crescimento & desenvolvimento , Sinergismo Farmacológico , Glucosiltransferases/biossíntese , Humanos , Streptococcus mutans/enzimologia , Streptococcus mutans/metabolismo
14.
Arch Oral Biol ; 51(11): 1015-23, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16806047

RESUMO

BACKGROUND/OBJECTIVE: Benzimidazoles are widely used as proton-pump inhibitors to control stomach hyperacidity and have been found also to have antimicrobial actions against Helicobacter pylori and oral streptococci. Our primary aim was to determine if they are active also against oral anaerobes associated with gingivitis. Our major focus was on catabolism because it leads to production of inflammatory metabolites such as butyrate and ammonia. The benzimidazoles are effective in the protonated form at acid pH values and cause irreversible inhibition of enzymes associated with formation of drug-target disulfide bonds. METHODS: Fusobacterium nucleatum ATCC 25586 and Prevotella intermedia ATCC 25611 were grown anaerobically in suspension cultures, harvested, washed and exposed to the benzimidazole lansoprazole at pH values of 4 or 5 before being washed and used for standard assays to detect inhibition of catabolic functions, uptake of the agent and lethality. RESULTS: Lansoprazole was found to be a bacteriostatic, multi-target antimicrobial against F. nucleatum under anaerobic conditions inhibitory for amino acid fermentation and also for glycolysis of glucose or fructose. ID(50) values for fermentation of amino acids and dipeptides by F. nucleatum ranged from 0.05 mM for lysine to 0.25 mM for serine. Fructose catabolism was highly sensitive with an ID(50) value of 0.03 mM apparently related to high sensitivity of the phosphoenolpyruvate:fructose phosphotransferase system, while the ID(50) for glucose catabolism by intact cells was some 0.07 mM. Fermentation of aspartate or aspartylaspartate by P. intermedia was found to be lansoprazole-sensitive with ID(50) values of about 0.18 and 0.20 mM, respectively. CONCLUSION: Catabolism of amino acids, dipeptides and sugars by oral anaerobes associated with gingivitis are sensitive to the inhibitory actions of lansoprazole. Thus, catabolic pathways are potential targets for use of benzimidazoles against bacteria involved in gingivitis.


Assuntos
2-Piridinilmetilsulfinilbenzimidazóis/farmacologia , Anti-Infecciosos/farmacologia , Fusobacterium nucleatum/efeitos dos fármacos , Boca/microbiologia , Prevotella intermedia/efeitos dos fármacos , Aminoácidos/metabolismo , Aminopeptidases/antagonistas & inibidores , Anaerobiose/fisiologia , Inibidores Enzimáticos/farmacologia , Fermentação , Frutose/metabolismo , Fusobacterium nucleatum/metabolismo , Glucose , Ácido Glutâmico/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Lansoprazol , Lisina/metabolismo , Oxigênio/metabolismo , Prevotella intermedia/metabolismo , Serina/metabolismo
15.
Artigo em Inglês | MEDLINE | ID: mdl-26937154

RESUMO

Since the isolation of the first cytokinin almost 60 yr ago, cytokinins have become critically important for ornamental and agricultural crops in plant tissue culture. Despite the extensive research on this class of compounds, little information is available on the chemical stability of cytokinins in solution or following an autoclave cycle with Murashige and Skoog (MS) basal medium. This work describes the stability in aqueous solutions of five widely used adenine-based cytokinins: trans-zeatin (tZ), 6-(γ,γ-dimethylallylamino) purine (2iP), kinetin, benzyladenine (BA), and m-topolin. High pressure liquid chromatography (HPLC) and electrospray ionization-mass spectrometry (ESI-MS) were used to quantify and identify their degradation. BA, kinetin, 2iP, and m-topolin were stable at 1.0 mg mL-1 in 0.05 N KOH, with no statistically significant concentration changes (p > 0.05) after 90 d of storage at temperatures of -20°C, 2-6°C, or 25°C. The cytokinin tZ was used as a model compound to evaluate stability under alkaline and acid conditions as well as after repeated freeze-thaw cycles. Trans-zeatin retained >90% of the initial concentration of 1.0 mg mL-1 when dissolved in 0.01 N KOH and stored at -20°C and 2-6°C for 90 d, with only the 2-6°C temperature treatment showing a statistical significant concentration change (p = 0.03). The 1.0 mg mL-1 tZ solution in 0.01 N KOH was stable through six repeated freeze-thaw cycles over 90 d without any significant change in concentration compared to the initial freeze-thaw. Yet, tZ showed highly significant concentration changes when dissolved at 50 mg mL-1 and 0.5 N KOH. All of these adenine-based cytokinins showed exceptional stability following an autoclave cycle at 121°C, 110 kPa for 30 min when in solutions of 1.0 mg mL-1 in 0.05 N KOH, with no significant degradation detected. Trans-zeatin was also found to be stable after one autoclave cycle with 1× MS-basal salts.

16.
Arch Oral Biol ; 50(8): 747-57, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15958206

RESUMO

OBJECTIVE: Zinc is used in oral care products as an antiplaque/antigingivitis agent. Our objective was to assess the antimicrobial actions of zinc against oral anaerobes associated with gingivitis, specifically Fusobacterium nucleatum and Prevotella intermedia, with focus on catabolism and oxidative metabolism. METHODS: The oral anaerobes were grown in complex medium in an anaerobic chamber, harvested by centrifugation and used directly for experiments with suspensions. Biofilm growth involved super-infection by F. nucleatum of an initial biofilm formed by Streptococcus sanguis. RESULTS: Zn(2+) inhibited catabolism of glutamate, glutamyl-glutamate, glucose and fructose by F. nucleatum cells in suspensions with ID(50) values, respectively, of 0.05, 0.005, 0.01 and 0.01 mM. The ID(50) value for inhibition of glutamate catabolism by biofilms was 0.10 mM. Inhibition of glutamate catabolism could be related to inhibition of substrate uptake and of 2-oxoglutarate reductase. Zn(2+) also inhibited catabolism of aspartate or aspartyl-aspartate by P. intermedia with ID(50) values of 0.07 and about 0.03 mM, respectively. Respiration of intact cells of F. nucleatum and NADH oxidase in cell extracts were sensitive to zinc with ID(50) values, respectively, of about 1.0 and 1.4 mM. Zinc also inhibited production of hydrogen peroxide by F. nucleatum (ID(50) = ca. 0.04 mM.) but at high concentrations acted to potentiate and enhance peroxide killing of the anaerobe. CONCLUSION: Zn(2+) is a potent inhibitor of catabolism by F. nucleatum and P. intermedia, including catabolism of peptides, which can be degraded to yield inflammatory metabolic end products. Zn(2+) also inhibits O(2) metabolism of F. nucleatum by about 50% and hydrogen peroxide production nearly completely but also enhances killing by peroxide added to cells.


Assuntos
Antibacterianos/farmacologia , Fusobacterium nucleatum/efeitos dos fármacos , Prevotella intermedia/efeitos dos fármacos , Zinco/farmacologia , Anaerobiose/fisiologia , Ácido Aspártico/metabolismo , Meios de Cultura , Frutose/metabolismo , Fusobacterium nucleatum/metabolismo , Gengivite/microbiologia , Glucose/metabolismo , Glutamato Desidrogenase/metabolismo , Glutamatos/metabolismo , Glicólise/efeitos dos fármacos , Humanos , Ácidos Cetoglutáricos/metabolismo , Boca/microbiologia , Oxirredução , Consumo de Oxigênio/fisiologia , Peróxidos/metabolismo , Prevotella intermedia/metabolismo
17.
Nanoscale ; 7(6): 2587-96, 2015 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-25578390

RESUMO

We have studied adsorption in regular, self-ordered alumina pores open at both ends or only at one end. The straight, non-connected pores have diameters ranging from 22 to 83 nm, with a relative dispersion below 1% in the pore size. Adsorption isotherms measured in open pores with a torsional microbalance show pronounced hysteresis loops characterized by nearly vertical and parallel adsorption and desorption branches. Blocking one end of the pores with glue has a strong influence on adsorption, as expected from classical macroscopic arguments. However, the experimental measurements show an unexpectedly rich phenomenology dependent on the pore size. For large pores (Dp ≥ 67 nm), the isotherms for closed end pores present much narrower hysteresis loops whose adsorption and desorption boundaries envelop the desorption branches of the isotherms for the corresponding open pores of the same size. The loop for small closed end pores (Dp = 22 nm) is slightly wider than that for open pores while the adsorption branches coincide. For large pores, in contrast, the desorption branches of pores with the same Dp overlap regardless of the pore opening. These observations are in agreement with our grand canonical Monte Carlo (GCMC) simulations for a cylindrical pore model with constrictions, suggesting that the alumina pores could be modeled using a constricted pore model whose adsorption isotherm depends on the ratio of the constriction size to the pore size (Dc/Dp).

18.
J Colloid Interface Sci ; 396: 242-50, 2013 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-23403112

RESUMO

We present a detailed simulation study of the hysteresis loop in conical pores and in cylindrical pores with periodic constrictions to understand how the non-uniformity of the pore diameter along the pore axis would affect the hysteresis loop. The shape and size of the loop in the conical pores (with and without closed ends) are modified by the cone angle because of the change in the curvature of the menisci at the pore ends. In periodically constricted cylindrical pores, the shape and size of the hysteresis loop are not significantly altered by the pore length or by the presence of a closed end because condensation and evaporation in this type of pore occur in the individual pore sections. Similar hysteresis loops have been found in experimental studies, suggesting that structures of the type modelled here occur in real materials.

19.
J Phys Chem B ; 115(42): 12160-72, 2011 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-21905696

RESUMO

We present a grand canonical Monte Carlo (GCMC) simulation of argon adsorption in connected cylindrical pores at 87.3 K. A number of pore models are constructed from various components: finite cylinder, finite cone, and flat surface. In the case of two cylinders of different sizes connected to each other with open ends, the adsorption isotherm can be described by a combination of two independent pores, the smaller of which is opened at both ends while the larger one is closed at one end. The adsorption isotherm depends on the relative size between the two sections of the connected pore. In the case of a cavity connected to the bulk surrounding gas via one or two narrower cylindrical necks, the phenomenon of either pore blocking or cavitation is observed, depending on the relative size between the neck and the cavity. If the neck size is smaller than a critical size, D(c), we observe cavitation, while pore blocking is observed when it is greater than D(c). This is due to the dominance of one of two mechanisms for removal of the adsorbates: either the receding of the menisci or the stretching of the fluid in the cavity. We also explore the effects of neck length and cavity length on the adsorption isotherm and conclude that while the neck length has a negligible effect on cavitation, it is of considerable importance when pore blocking occurs, because this process is controlled by the formation and movement of the meniscus in the pore neck. The effect of cavity length is found to be negligible in both cases.

20.
Artigo em Inglês | MEDLINE | ID: mdl-21426213

RESUMO

Pain is a major concern of cancer patients and a significant problem for therapy. Pain can become a predominant symptom in advanced cancers. In this open-label clinical study, the authors have treated 26 cancer patients who have been declared as terminal without the option of conventional treatment. These patients suffered from high levels of pain that was poorly managed by all available interventional approaches recommended by World Health Organization (WHO) guideline. The results indicate that intravenous infusion of dimethyl sulfoxide (DMSO) and sodium bicarbonate (SB) solution can be a viable, effective, and safe treatment for refractory pain in cancer patients. These patients had pain due to the disease progression and complication of chemotherapy and radiation. Moreover, the preliminary clinical outcome of 96-day follow-up suggests that the application of DMSO and SB solution intravenously could lead to better quality of life for patients with nontreatable terminal cancers. The data of this clinical observation indicates that further research and application of the DMSO and SB combination may help the development of an effective, safe, and inexpensive therapy to manage cancer pain.


Assuntos
Dimetil Sulfóxido/farmacologia , Neoplasias/complicações , Dor Intratável/tratamento farmacológico , Bicarbonato de Sódio/farmacologia , Adolescente , Adulto , Idoso , Analgésicos/administração & dosagem , Analgésicos/efeitos adversos , Analgésicos/farmacologia , Dimetil Sulfóxido/administração & dosagem , Dimetil Sulfóxido/efeitos adversos , Combinação de Medicamentos , Feminino , Seguimentos , Humanos , Infusões Intravenosas , Masculino , Pessoa de Meia-Idade , Dor Intratável/etiologia , Qualidade de Vida , Bicarbonato de Sódio/administração & dosagem , Bicarbonato de Sódio/efeitos adversos , Resultado do Tratamento , Adulto Jovem
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