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1.
Mol Pharm ; 17(10): 3885-3899, 2020 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-32787269

RESUMO

Boron neutron capture therapy (BNCT) for cancer is on the rise worldwide due to recent developments of in-hospital neutron accelerators which are expected to revolutionize patient treatments. There is an urgent need for improved boron delivery agents, and herein we have focused on studying the biochemical foundations upon which a successful GLUT1-targeting strategy to BNCT could be based. By combining synthesis and molecular modeling with affinity and cytotoxicity studies, we unravel the mechanisms behind the considerable potential of appropriately designed glucoconjugates as boron delivery agents for BNCT. In addition to addressing the biochemical premises of the approach in detail, we report on a hit glucoconjugate which displays good cytocompatibility, aqueous solubility, high transporter affinity, and, crucially, an exceptional boron delivery capacity in the in vitro assessment thereby pointing toward the significant potential embedded in this approach.


Assuntos
Terapia por Captura de Nêutron de Boro/métodos , Boro/administração & dosagem , Portadores de Fármacos/efeitos da radiação , Glucose/efeitos da radiação , Isótopos/administração & dosagem , Neoplasias/radioterapia , Boro/farmacocinética , Linhagem Celular Tumoral , Portadores de Fármacos/síntese química , Portadores de Fármacos/farmacocinética , Liberação Controlada de Fármacos/efeitos da radiação , Glucose/análogos & derivados , Glucose/síntese química , Glucose/farmacocinética , Transportador de Glucose Tipo 1/metabolismo , Humanos , Isótopos/farmacocinética , Simulação de Acoplamento Molecular
2.
Nutrients ; 10(2)2018 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-29443904

RESUMO

Minimally processed cereal breakfast products from whole grain entered the market due to consumer demand of more nutritional food with more controlled sugar release. However, the subsequent processing of such products with different cooking methods in the consumer's kitchen may lead to significant differentiation of their nutritional value. Therefore, the evaluation of the impact of frequently used cooking methods on a final quality of breakfast cereals meal is needed. The present study investigates how the two different methods of heating, conventional and microwave (MW) assisted, affect the carbohydrate content, profile and resulting glycemic index of so prepared food as well as the antioxidant activity of meals. Two products available on the market-oat bran and flakes-were used. The highest starch content in fluid phase of oatmeal was detected in samples heated for 3 min with microwaves, regardless the type. The lowest starch content was obtained for 5 min MW heated flakes sample. The total content of glucose was about 1.5 times lower in bran vs. flakes oatmeal. The highest ß-glucan content in fluid fraction was also observed for bran meal but its release was independent of applied conditions.


Assuntos
Antioxidantes/análise , Avena/química , Culinária , Carboidratos da Dieta/análise , Índice Glicêmico , Micro-Ondas , Grãos Integrais/química , Adulto , Antioxidantes/química , Antioxidantes/efeitos da radiação , Avena/efeitos da radiação , Desjejum , Carboidratos da Dieta/efeitos da radiação , Glucose/análise , Glucose/química , Glucose/efeitos da radiação , Índice Glicêmico/efeitos da radiação , Humanos , Micro-Ondas/efeitos adversos , Valor Nutritivo , Tamanho da Partícula , Período Pós-Prandial , Solubilidade , Amido/análise , Amido/química , Amido/efeitos da radiação , Viscosidade/efeitos da radiação , Água/análise , Grãos Integrais/efeitos da radiação , Adulto Jovem , beta-Glucanas/análise , beta-Glucanas/química , beta-Glucanas/efeitos da radiação
3.
J Phys Chem B ; 122(1): 19-27, 2018 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-29210267

RESUMO

We have investigated the photodynamics of ß-d-glucose employing our field-induced surface-hopping (FISH) method, which allows us to simulate the coupled electron-nuclear dynamics, explicitly including nonadiabatic effects and light-induced excitation. Our results reveal that from the initially populated S1 and S2 states, glucose returns nonradiatively to the ground state within about 200 fs. This takes place mainly via conical intersections (CIs), whose geometries in most cases involve the elongation of a single O-H bond, whereas in some instances, ring-opening due to dissociation of a C-O bond is observed. Experimentally, excitation to a distinct excited electronic state is improbable due to the presence of a dense manifold of states bearing similar oscillator strengths. Our FISH simulations, explicitly including a UV laser pulse of 6.43 eV photon energy, reveal that after initial excitation, the population is almost equally spread over several close-lying electronic states. This is followed by a fast nonradiative decay on the time scale of 100-200 fs, with the final return to the ground state proceeding via the S1 state through the same types of CIs as observed in the field-free simulations.


Assuntos
Glucose/química , Glucose/efeitos da radiação , Simulação de Dinâmica Molecular , Espectrofotometria Ultravioleta , Raios Ultravioleta
4.
Exp Toxicol Pathol ; 68(6): 355-63, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27210074

RESUMO

INTRODUCTION: The objective of this study was to conduct a 14-day toxicology assessment for intravenous solutions prepared from irradiated resuscitation fluid components and sterile water. METHODS: Healthy Sprague Dawley rats (7-10/group) were instrumented and randomized to receive one of the following Field IntraVenous Resuscitation (FIVR) or commercial fluids; Normal Saline (NS), Lactated Ringer's, 5% Dextrose in NS. Daily clinical observation, chemistry and hematology on days 1,7,14, and urinalysis on day 14 were evaluated for equivalence using a two sample t-test (p<0.05). A board-certified pathologist evaluated organ histopathology on day 14. RESULTS: Equivalence was established for all observation parameters, lactate, sodium, liver enzymes, creatinine, WBC and differential, and urinalysis values. Lack of equivalence for hemoglobin (p=0.055), pH (p=0.0955), glucose (p=0.0889), Alanine-Aminotransferase (p=0.1938), albumin (p=0.1311), and weight (p=0.0555, p=0.1896), was deemed not clinically relevant due to means within physiologically normal ranges. Common microscopic findings randomly distributed among animals of all groups were endocarditis/myocarditis and pulmonary lesions. DISCUSSION: These findings are consistent with complications due to long-term catheter use and suggest no clinically relevant differences in end-organ toxicity between animals infused with FIVR versus commercial fluids.


Assuntos
Hidratação/métodos , Glucose/efeitos da radiação , Soluções Isotônicas/efeitos da radiação , Cloreto de Sódio/efeitos da radiação , Esterilização/métodos , Animais , Modelos Animais de Doenças , Feminino , Masculino , Ratos , Ratos Sprague-Dawley , Lactato de Ringer
5.
J Biomed Nanotechnol ; 11(6): 988-96, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26353588

RESUMO

The highly sensitive, interference-free and non-enzymatic optical sensing of glucose has been made possible for the first time using the hydrothermally synthesized ZnO nanorods. The UV irradiation of glucose-treated ZnO nanorods decomposes glucose into hydrogen peroxide (H2O2) and gluconic acid by UV oxidation. The ZnO nanorods play the role of a catalyst similar to the oxidase used in the enzymatic glucose sensors. The photoluminescence (PL) intensity of the near-band edge emission of the ZnO nanorods linearly decreased with the increased concentration of H2O2. Therefore, the glucose concentration is monitored over the wide range of 0.5-30 mM, corresponding to 9-540 mg/dL. The concentration range of the linear region in the calibration curve is suitable for its clinical use as a glucose sensor, because the glucose concentration of human serum is typically in the range of 80-120 mg/dL. In addition, the optical glucose sensor made of the ZnO nanorods is free from interference by bovin serum albumin, ascorbic acid or uric acid, which are also present in human blood. The non-enzymatic ZnO-nanorod sensor has been demonstrated with human serum samples from both normal persons and diabetic patients. There is a good agreement between the glucose concentrations measured by the PL quenching and standard clinical methods.


Assuntos
Técnicas Biossensoriais/instrumentação , Glucose/análise , Nanotubos/química , Dispositivos Ópticos , Óxido de Zinco/química , Análise Química do Sangue/instrumentação , Glicemia/análise , Diabetes Mellitus/sangue , Gluconatos/química , Gluconatos/efeitos da radiação , Glucose/química , Glucose/efeitos da radiação , Humanos , Peróxido de Hidrogênio/química , Peróxido de Hidrogênio/efeitos da radiação , Membranas Artificiais , Raios Ultravioleta
6.
Bioresour Technol ; 187: 205-213, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25855526

RESUMO

Pre-treatment of macroalgae has received considerable research globally due to its influence on the technical, economic and environmental sustainability of algae biogas production. Some of the most promising pre-treatment methods require the application of chemicals, enzymatic, and mechanical. This study focused on these pre-treatments of Ulva rigida for biogas production. The evaluation of different pre-treatment in terms of reducing sugar yields demonstrates that 3.62, 2.88, 2.53 and 7.3g/L of reducing sugar was obtained in acid catalysis, thermoalkaline, ultrasonication and enzymatic pre-treatment, respectively. However in crude macroalgae only 0.6g/L of reducing sugar was given. After anaerobic digestion, the enzymatic hydrolysis was demonstrated the best biogas yield than other pre-treatment which reached 626.5mL/gCODint with 62.65% of biodegradability. The best demonstrated method which uses crude broth of Aspergillus niger showed an effective and environmentally friendly strategy for enhancing the biogas production yields after the anaerobic digestion.


Assuntos
Glucose/química , Glucose/metabolismo , Hidrolases/química , Metano/biossíntese , Ulva/metabolismo , Ácidos/química , Álcalis/química , Anaerobiose , Catálise , Glucose/efeitos da radiação , Temperatura Alta , Hidrólise , Metano/isolamento & purificação , Oxirredução , Hidróxido de Sódio/química , Sonicação , Ácidos Sulfúricos/química , Ondas Ultrassônicas , Ulva/efeitos da radiação
7.
Metab Brain Dis ; 30(3): 829-37, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25796222

RESUMO

Near infrared radiation (NIR) has been shown to be neuroprotective against neurological diseases including stroke and brain trauma, but the underlying mechanisms remain poorly understood. In the current study we aimed to investigate the hypothesis that NIR may protect neurons by attenuating oxygen-glucose deprivation (OGD)-induced nitric oxide (NO) production and modulating cell survival/death signaling. Primary mouse cortical neurons were subjected to 4 h OGD and NIR was applied at 2 h reoxygenation. OGD significantly increased NO level in primary neurons compared to normal control, which was significantly ameliorated by NIR at 5 and 30 min post-NIR. Neither OGD nor NIR significantly changed neuronal nitric oxide synthase (nNOS) mRNA or total protein levels compared to control groups. However, OGD significantly increased nNOS activity compared to normal control, and this effect was significantly diminished by NIR. Moreover, NIR significantly ameliorated the neuronal death induced by S-Nitroso-N-acetyl-DL-penicillamine (SNAP), a NO donor. Finally, NIR significantly rescued OGD-induced suppression of p-Akt and Bcl-2 expression, and attenuated OGD-induced upregulation of Bax, BAD and caspase-3 activation. These results suggest NIR may protect against OGD at least partially through reducing NO production by down-regulating nNOS activity, and modulating cell survival/death signaling.


Assuntos
Regulação para Baixo/efeitos da radiação , Glucose/deficiência , Glucose/efeitos da radiação , Raios Infravermelhos , Óxido Nítrico Sintase Tipo I/metabolismo , Óxido Nítrico Sintase Tipo I/efeitos da radiação , Animais , Hipóxia Celular/fisiologia , Hipóxia Celular/efeitos da radiação , Células Cultivadas , Córtex Cerebral/metabolismo , Córtex Cerebral/efeitos da radiação , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/metabolismo , Neurônios/efeitos da radiação , Oxirredução/efeitos da radiação , Oxigênio/metabolismo , Oxigênio/efeitos da radiação , Gravidez
8.
J Radiat Res ; 55(4): 726-9, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24672022

RESUMO

We investigated stable radicals produced by 0.25-4.5 Gy doses of X-ray irradiation of sucrose. Electron spin resonance (ESR) is able to observe the signal from sucrose irradiated at 0.25 Gy. The ESR signal intensity of the radicals is related to the accumulated dose, and it increases linearly with increasing absorbed dose. In addition, we examined the effect of dose rate (0.50-1.5 Gy/min) on the signal intensity of the irradiated sucrose. The stable radical production did not exhibit dose rate dependence. In addition, the peak corresponding to the irradiated glucose was observed to increase more with increasing absorbed dose than the peak corresponding to irradiated fructose. Therefore, the present ESR results regarding the 0.25-4.5 Gy irradiation of sucrose provide new insights into a possible sucrose ESR dosimeter.


Assuntos
Sacarose/química , Sacarose/efeitos da radiação , Espectroscopia de Ressonância de Spin Eletrônica , Radicais Livres/química , Radicais Livres/efeitos da radiação , Frutose/química , Frutose/efeitos da radiação , Glucose/química , Glucose/efeitos da radiação , Doses de Radiação , Radiometria
9.
Radiats Biol Radioecol ; 52(1): 50-7, 2012.
Artigo em Russo | MEDLINE | ID: mdl-22568014

RESUMO

The aim of this work was to determine which processes in air-dry seeds result in bimodal changes of the pea seed quality under the influence of low doses of gamma-radiation. Pea seeds (cv. "Nemchinovsky-85", harvest 2006, 82% germination persentage) were exposed to gamma-radiation at doses of 3, 10 and 100 Gy The germination percentage decreased to 45% four days after irradiation at the dose of 3 Gy, rised up to 87% at doses of 10 Gy, while the dose of 100 Gy killed the most part of seeds. Seed fractions differing in quality were selected using the metod of Room temperature phosphorecsence (RTP): strong seed frasction I from non-irradiated seeds; weak seed fraction II from the seeds irradiated at a dose of 3 Gy; dead seeds from the seeds irradiated at a dose of 100 Gy. ThermoChemiLuminecnsece (TCL) of seed powders and cotyledons was used. It was shown that the increase of the TCL level in the temperature range from 50 to 110 degreesC was associated with the lipid peroxidation products. The TCL level of seeds subjected to gamma-irradiation at a dose of 3 Gy was similar to that of non-irradiated seeds in the temperature range 50 to 100 degreesC. Therefore, lipid peroxidation was not the cause of the abnormal seedling appearance. The TCL level within this temperature range was increased only in seeds subjected to y-irradiation at a dose of 100 Gy. The TCL level at 150 degreesC was in proportion with the exogenous glucose amount. The increased TCL level of seeds subjected to y-irradiation at a dose of 3 Gy at 150 degreesC resulted from the increase of the glucose content. This means that the transition from the fraction of strong seeds into the fraction of weak ones was the result of the activation of hydrolysis processes. Decrease in the water content of seeds testified to utilization of bound water in this process. The decrease of the glucose content in the "improved" seeds subjected to gamma-irradiation at a dose of 10 Gy most probably indicates the participation of glucose in the amino carbonyl reaction. The latter could be the reason for the increased water content in the "improved" seeds and a decreased water permeability of cell membranes.


Assuntos
Glucose/metabolismo , Peroxidação de Lipídeos/efeitos da radiação , Medições Luminescentes/métodos , Pisum sativum/efeitos da radiação , Sementes/efeitos da radiação , Raios gama , Glucose/efeitos da radiação , Metabolismo dos Lipídeos/efeitos da radiação , Pisum sativum/metabolismo , Doses de Radiação
10.
Bioresour Technol ; 102(24): 11254-7, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22014701

RESUMO

Glucose was oxidized in the presence of powdered TiO(2) photocatalysts synthesized by an ultrasound-promoted sol-gel method. The catalysts were more selective towards glucaric acid, gluconic acid and arabitol (total selectivity approx. 70%) than the most popular photocatalyst, Degussa P-25. The photocatalytic systems worked at mild reaction conditions: 30°C, atmospheric pressure and very short reaction time (e.g. 5 min). Such relatively good selectivity towards high-valued molecules are attributed to the physico-chemical properties (e.g. high specific surface area, nanostructured anatase phase, and visible light absorption) of novel TiO(2) materials and the reaction conditions. The TiO(2) photocatalysts have potential for water purification and energy production and for use in the pharmaceutical, food, perfume and fuel industries.


Assuntos
Glucose/química , Glucose/efeitos da radiação , Luz , Nanoestruturas/química , Compostos Orgânicos/análise , Titânio/química , Catálise/efeitos da radiação , Oxirredução/efeitos da radiação
11.
Carbohydr Res ; 346(15): 2469-81, 2011 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-21906727

RESUMO

All eight D-aldohexoses and aldohexoses derived from the non-reducing end of disaccharides were investigated by variable-wavelength infrared multiple-photon dissociation (IRMPD) as anions in the negative-ion mode. Spectroscopic evidence supports the existence of a relatively abundant open-chain configuration of the anions in the gas phase, based on the observation of a significant carbonyl absorption band near 1710 cm(-1). The abundance of the open-chain configuration of the aldohexose anions was approximately 1000-fold or greater than that of the neutral sugars in aqueous solution. This provides an explanation as to why it has not been possible to discriminate the anomeric configuration of aldohexose anions in the gas phase when derived from the non-reducing sugar of a disaccharide. Evidence from photodissociation spectra also indicates that the different aldohexoses yield product ions with maximal abundances at different wavelengths, and that the carbonyl stretch region is useful for differentiation of sugar stereochemistries. Quantum-chemical calculations indicate relatively low energy barriers to intramolecular proton transfer between hydroxyl groups and adjacent alkoxy sites located on open-chain sugar anions, suggesting that an ensemble of alkoxy charge locations contributes to their observed photodissociation spectra. Ring opening of monosaccharide anions and interconversion among configurations is an inherent property of the ions themselves and occurs in vacuo independent of solvent participation.


Assuntos
Dissacarídeos/química , Hexoses/química , Raios Infravermelhos , Ânions , Configuração de Carboidratos , Análise de Fourier , Galactose/química , Galactose/efeitos da radiação , Gases , Glucose/química , Glucose/efeitos da radiação , Hexoses/efeitos da radiação , Ligação de Hidrogênio , Lactonas/química , Lactonas/efeitos da radiação , Lasers , Manose/química , Manose/efeitos da radiação , Espectrometria de Massas , Modelos Moleculares , Espectrofotometria Infravermelho
15.
JAMA ; 305(8): 808-13, 2011 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-21343580

RESUMO

CONTEXT: The dramatic increase in use of cellular telephones has generated concern about possible negative effects of radiofrequency signals delivered to the brain. However, whether acute cell phone exposure affects the human brain is unclear. OBJECTIVE: To evaluate if acute cell phone exposure affects brain glucose metabolism, a marker of brain activity. DESIGN, SETTING, AND PARTICIPANTS: Randomized crossover study conducted between January 1 and December 31, 2009, at a single US laboratory among 47 healthy participants recruited from the community. Cell phones were placed on the left and right ears and positron emission tomography with ((18)F)fluorodeoxyglucose injection was used to measure brain glucose metabolism twice, once with the right cell phone activated (sound muted) for 50 minutes ("on" condition) and once with both cell phones deactivated ("off" condition). Statistical parametric mapping was used to compare metabolism between on and off conditions using paired t tests, and Pearson linear correlations were used to verify the association of metabolism and estimated amplitude of radiofrequency-modulated electromagnetic waves emitted by the cell phone. Clusters with at least 1000 voxels (volume >8 cm(3)) and P < .05 (corrected for multiple comparisons) were considered significant. MAIN OUTCOME MEASURE: Brain glucose metabolism computed as absolute metabolism (µmol/100 g per minute) and as normalized metabolism (region/whole brain). RESULTS: Whole-brain metabolism did not differ between on and off conditions. In contrast, metabolism in the region closest to the antenna (orbitofrontal cortex and temporal pole) was significantly higher for on than off conditions (35.7 vs 33.3 µmol/100 g per minute; mean difference, 2.4 [95% confidence interval, 0.67-4.2]; P = .004). The increases were significantly correlated with the estimated electromagnetic field amplitudes both for absolute metabolism (R = 0.95, P < .001) and normalized metabolism (R = 0.89; P < .001). CONCLUSIONS: In healthy participants and compared with no exposure, 50-minute cell phone exposure was associated with increased brain glucose metabolism in the region closest to the antenna. This finding is of unknown clinical significance.


Assuntos
Encéfalo/metabolismo , Encéfalo/efeitos da radiação , Telefone Celular , Glucose/metabolismo , Glucose/efeitos da radiação , Ondas de Rádio/efeitos adversos , Absorção , Adulto , Encéfalo/diagnóstico por imagem , Estudos Cross-Over , Campos Eletromagnéticos/efeitos adversos , Exposição Ambiental , Feminino , Fluordesoxiglucose F18 , Humanos , Masculino , Tomografia por Emissão de Pósitrons , Compostos Radiofarmacêuticos
17.
Vox Sang ; 101(1): 35-43, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21175668

RESUMO

BACKGROUND: A novel short-wave ultraviolet light (UVC) pathogen reduction technology (THERAFLEX UV-Platelets; MacoPharma, Mouvaux, France) without the need of any additional photoactive reagent has recently been evaluated for various bacteria and virus infectivity assays. The use of UVC alone has on the one hand been shown to reduce pathogens but may, on the other hand, have some impact on the platelet (PLT) quality. The purpose of this study was to determine the potential effects on PLT quality of pathogen inactivation treatment using the novel UVC method for PLT concentrates. STUDY DESIGN AND METHODS: Buffy-coat-derived PLTs suspended in SSP+ were irradiated with UVC light in plastic bags (MacoPharma) made of ethyl vinyl acetate, considered to be highly permeable to UVC light. The UVC-treated (test, n=8) as well as the untreated (reference, n=8) PLT units were stored in PLT storage bags composed of n-butyryl, tri n-hexyl citrate-plasticized polyvinyl chloride (MacoPharma) on a flat bed agitator for in vitro testing during 7 days of storage. RESULTS: No significant difference in PLT counts and lactate dehydrogenase between the groups was detected. During storage, glucose decreased more and lactate increased more in the test units. Statistically significant differences were found for glucose (P<0·01) and lactate (P<0·05) on day 7. ATP levels were higher (P<0·01 from day 5) in the reference units. With exception of day 7 (P<0·01 reference vs. test), hypotonic shock response reactivity was not different between groups. Extent of shape change was lower (P<0·01), and CD62P (P<0·05 day 5) was higher in the test units. CD42b and CD41/61 showed similar trends throughout storage, without any significant difference between the units. pH was maintained at >6·8 (day 7) and swirling remained at the highest level (score = 2) for all units throughout storage. CONCLUSION: Our results suggest that irradiation with UVC light has a slight impact on PLT in vitro quality and appears to be insignificant with regard to current in vitro standards.


Assuntos
Trifosfato de Adenosina/metabolismo , Plaquetas/metabolismo , Plaquetas/efeitos da radiação , Preservação de Sangue/métodos , Glucose/metabolismo , Ácido Láctico/metabolismo , Raios Ultravioleta , Trifosfato de Adenosina/efeitos da radiação , Bactérias/crescimento & desenvolvimento , Bactérias/efeitos da radiação , Plaquetas/microbiologia , Glucose/efeitos da radiação , Humanos , Integrina beta3/metabolismo , Integrina beta3/efeitos da radiação , L-Lactato Desidrogenase/metabolismo , L-Lactato Desidrogenase/efeitos da radiação , Ácido Láctico/efeitos da radiação , Selectina-P/metabolismo , Selectina-P/efeitos da radiação , Contagem de Plaquetas , Complexo Glicoproteico GPIb-IX de Plaquetas/metabolismo , Complexo Glicoproteico GPIb-IX de Plaquetas/efeitos da radiação , Glicoproteína IIb da Membrana de Plaquetas/metabolismo , Glicoproteína IIb da Membrana de Plaquetas/efeitos da radiação
19.
J Photochem Photobiol B ; 98(3): 216-22, 2010 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-20149676

RESUMO

In a paper by Amat et al. (Modification of the intrinsic fluorescence and biochemical behavior of adenosine triphosphate ATP after irradiation with visible and near-infrared laser light, J. Photochem. Photobiol. B 81 (2005) 26-32) it was shown that the conversion of glucose to glucose-6-phosphate by hexokinase in vitro was accelerated when ATP, which supplies the reaction with energy, was priorly irradiated at non-resonant optical frequencies (NROF, i.e., 655 and 830 nm). Correspondingly, the authors postulated that NROF may lower the energy barrier for the dephosphorylation of ATP's terminal phosphate and thus accelerate the reaction rate through a more expeditious energy delivery. Next to the established photobiostimulatory influence of visible light on cells, which is mediated by cytochrome c oxidase through resonant effects of light, Amat et al. posited an interesting theory with which the same processes could be induced through non-resonant effects. To investigate the effects of NROF with respect to the hexokinase reaction in greater detail, the reaction rates were measured spectrofluorometrically after 633-nm laser irradiation of ATP, the ATP-Mg complex, hexokinase, and the entire reaction mixture at room temperature (22 degrees C) and at the optimal reaction temperature (30 degrees C). No differences in reaction rates between the NROF-irradiated and control groups were found at either temperature. The hypothesis that NROF enhances in vitro hexokinase activity by lowering the activation energy for the dephosphorylation of ATP's terminal phosphate by hexokinase was therefore disproven. Consequently, it is questionable, albeit not unequivocal, that NROF exerts an effect on other ATP-driven reactions in cell metabolic pathways through a direct impact on ATP.


Assuntos
Glucose/química , Hexoquinase/química , Lasers , Relação Dose-Resposta à Radiação , Ativação Enzimática/efeitos da radiação , Glucose/efeitos da radiação , Hexoquinase/efeitos da radiação , Fosforilação/efeitos da radiação , Doses de Radiação
20.
Carbohydr Res ; 345(3): 408-13, 2010 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-20060106

RESUMO

Glucose, galactose, and mannose in H(2)O and D(2)O were ionized by an atmospheric pressure chemical ionization (APCI) method. Isotope effects on fragmentation patterns of the monosaccharides were examined by deuterium replacement of the -OH groups to distinguish the isomers with a single mass spectrometer. The most abundant ions were the [M+H(2)O](+)() and [M(D5)+D+D(2)O](+) for using H(2)O and D(2)O as solvent and eluent, respectively. Major fragment ions were the [M-OH](+) and [M-OH-H(2)O](+) in H(2)O, while those in D(2)O were the [M(D5)+D-D(2)O](+) and [M(D5)+D-2D(2)O](+). The differences in the product ions generated in H(2)O and D(2)O were due to enhancement of the strength of hydrogen bonding by the deuterium replacement. Variations of the ion intensity ratios of the [M-OH](+)/[M-OH-H(2)O](+) and [M(D5)-OD](+)/[M(D5)-OD-D(2)O](+) with the fragmentor voltage showed different trends depending on the kind of monosaccharides. By comparing the ion intensity ratios of the [M+H(2)O](+)()/M(+)(), [M(D5)+D+D(2)O](+)/[M(D5)+D](+), [M-OH](+)/[M-OH-H(2)O](+), and [M(D5)+D-D(2)O](+)/[M(D5)+D-2D(2)O](+), it was possible to distinguish the isomers of monosaccharides.


Assuntos
Deutério , Galactose/química , Glucose/química , Íons/química , Manose/química , Pressão Atmosférica , Fenômenos Químicos , Medição da Troca de Deutério , Galactose/efeitos da radiação , Glucose/efeitos da radiação , Manose/efeitos da radiação
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