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1.
Phys Chem Chem Phys ; 26(15): 11618-11630, 2024 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-38546226

RESUMEN

In this work, CuM/CeO2 (M = Mn, Fe, Co, Ni, and Zr) catalysts with a low Cu content of 1 wt% were purposely designed and prepared using the co-impregnation method. The samples were characterized using various techniques (TG-DTA, XRD, N2-adsorption/desorption measurements, H2-TPR, XPS and Raman spectroscopy) and CO preferential oxidation (CO-Prox) under H2/CO2-rich conditions was performed. The results have shown that enhanced catalytic performance was achieved upon the introduction of Mn, Co and Ni, and little impact was observed with Zr doping, but Fe showed a negative effect, as compared with the Cu/CeO2 catalyst. Characterization data revealed that the M doping strongly changed the surface composition, revealing the decreased Cu/Ce ratios on the surface, which could be accounted for by the formation of more M/Cu-O-Ce solid solution, or strong Cu-M interactions. When Mn was used, the obtained CuMn/CeO2 catalyst revealed the highest concentration of the oxygen vacancies and Ce3+ ions, which could be correlated well with its superior catalytic performance. Compared with the Cu/CeO2 catalyst, the CO conversion rate increased by 24.7% at a low temperature of 90 °C over the CuMn/CeO2 catalyst. At 130 °C, the maximum CO conversion was 94.7% and the CO2 selectivity was 78.9%. Conversely, the Fe doped Cu/CeO2 catalyst demonstrated the poorest catalytic activity, which was due to the blockage effect of Fe species on Cu showing a high Fe/Cu ratio of 1.9 on the surface.

2.
Phys Chem Chem Phys ; 25(47): 32557-32568, 2023 Dec 06.
Artículo en Inglés | MEDLINE | ID: mdl-37999632

RESUMEN

The adsorption of O2 on Cu/CeO2(111) and the CO oxidation reactivity of the formed oxygen species were studied using the DFT method. The results showed that superoxide species (O2δ-), which directly interacted with Cu, formed when O2 adsorbed on the surface oxygen vacancies, while O2 adsorbed on the subsurface oxygen vacancies gave rise to ozone-like O3δ- species by combining with the nearest surface lattice oxygen (O1). PDOS showed that hybridization of the 2p orbitals between O2 and O1 formed a delocalized π bond, confirming the formation of O3δ-. For O2δ-, electrons on Cu and O1 transferred to O2 while the charge of Ce remained unchanged. However, for O3δ-, the transferred electrons were mainly from O1, and partially from O2, Ce1 and Ce2. It was very interesting that Cu also received a few electrons in the latter case. Compared with CO directly adsorbed on lattice oxygen, the two oxygen species were active for CO oxidation, forming CO2 or carbonates, and higher absolute adsorption energy was obtained with the interaction between CO and O3δ-. The findings of this study provide new insight on the CO oxidation reaction mechanism, facilitating an in-depth understanding of Cu-doped CeO2 catalysts.

3.
Chem Rec ; 16(1): 173-88, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26617399

RESUMEN

Transition-metal complex triplet photosensitizers are versatile compounds that have been widely used in photocatalysis, photovoltaics, photodynamic therapy (PDT) and triplet-triplet annihilation (TTA) upconversion. The principal photophysical processes in these applications are the intermolecular energy transfer or electron transfer. One of the major challenges facing these triplet photosensitizers is the short triplet-state lifetime, which is detrimental to the above-mentioned photophysical processes. In order to address this challenge, transition-metal complexes showing long-lived triplet excited states are highly desired. This review article summarizes the development of this fascinating area, including the molecular design rationales, the principal photophysical properties, and the applications of these complexes in PDT and TTA upconversion.

4.
J Org Chem ; 80(11): 5674-86, 2015 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-25941747

RESUMEN

Thiol-activated triplet-triplet annihilation (TTA) upconversion was studied with two different approaches, i.e., with 2,4-dinitrobenzenenesulfonyl (DNBS)-caged diiodoBodipy triplet photosensitizers (perylene as the triplet acceptor/emitter of the upconversion) and DNBS-caged Bodipy fluorophore as the triplet acceptor/emitter (PdTPTBP as the triplet photosensitizer, TPTBP = tetraphenyltetrabenzoporphyrin). The photophysical processes were studied with steady-state UV-vis absorption spectroscopy, fluorescence spectroscopy, electrochemical characterization, nanosecond transient absorption spectroscopy, and DFT/TDDFT computations. DNBS-caged triplet photosensitizer shows a shorter triplet state lifetime (24.7 µs) than the uncaged triplet photosensitizer (86.0 µs), and the quenching effect is due to photoinduced electron transfer (PET). TTA upconversion was enhanced upon cleavage of the DNBS moiety by thiols. On the other hand, the DNBS-caged Bodipy shows no fluorescence, but the uncaged fluorophore shows strong fluorescence; thus, TTA upconversion is able to be enhanced with the uncaged fluorophore as the triplet energy acceptor/emitter. The results indicate that the DNBS moiety exerts a significant quenching effect on the singlet excited state of Bodipy, but the quenching on the triplet excited state is much weaker. Calculation of the Gibbs free energy changes of the photoinduced electron transfer indicates that the singlet state gives a larger driving force for the PET process than the triplet state.

5.
Inorg Chem ; 54(15): 7492-505, 2015 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-26196211

RESUMEN

Broadband near-IR absorbing trans-bis(trialkylphosphine) Pt(II) bisacetylide binuclear complex (Pt-1) was prepared with boron-dipyrromethene (Bodipy) and styrylBodipy acetylide ligands. Pt-1 shows strong absorption bands at 731 and 503 nm. Singlet energy transfer (EnT) and efficient intersystem crossing of the central coordinated Bodipy ligand were proposed to be responsible for the efficient funneling of the excitation energy to the triplet-state manifold. Reference complexes containing only a single Bodipy ligand were prepared for comparison (with styrylBodipy ligand Pt-0 or Bodipy ligand Pt-2). The molecular structures were confirmed by single-crystal X-ray diffraction. The photophysical properties were studied with steady-state and time-resolved transient absorption spectroscopies, electrochemical characterization, and density functional theory/time-dependent density functional theory calculations. Dual fluorescence was observed for Pt-1. Singlet EnT in Pt-1 was proposed based on the fluorescence quenching/excitation spectra, and femtosecond transient absorption spectra (energy transfer rate constant kEnT = 2.2 × 10(10) s(-1)). With nanosecond transient absorption spectra, intramolecular triplet-state energy transfer in Pt-1 was proved. Gibbs free energy changes of charge separation indicate that the photoinduced intramolecular electron transfer in Pt-1 is thermodynamically prohibited. Intermolecular triplet transfer between Pt-2 and L-1 was studied with nanosecond transient absorption spectra; the EnT rate and energy transfer efficiency were determined as 3.6 × 10(4) s(-1) and 94.5%, respectively. The singlet oxygen ((1)O2) photosensitizing of Pt-1 was improved as compared to the complexes containing only a single visible-light-absorbing chromophore.

6.
Inorg Chem ; 54(16): 7803-17, 2015 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-26230144

RESUMEN

Pt(II) dbbpy bisacetylide (dbbpy = 4,4'-di(tert-butyl)-2,2'-bipyridine) complex (Pt-1) with two different Bodipy ligands was prepared with the goal to attain broad-band visible light absorbing, efficient funneling of the photoexcitation energy (via resonance energy transfer, RET) to the energy acceptor and high triplet formation quantum yields. Construction of the above-mentioned molecular structural motif is challenging because two different arylacetylide ligands are incorporated in the complex; normally two homoleptic acetylide ligands were used for this kind of N(∧)N Pt(II) complexes. A reference complex with trans bis(tributylphosphine) Pt(II) bisacetylide protocol (Pt-4) was prepared for comparison of the photophysical properties. The two different Bodipy ligands in Pt-1 and Pt-4 constitute singlet/triplet energy donor/acceptor, as a result the harvested photoexcitation energy can be funneled to the triplet state confined on one of the two Bodipy ligands. The photophysical properties of the complexes were studied with steady state UV-vis absorption and luminescence spectroscopies, femto- and nanosecond transient absorption spectroscopies, cyclic voltammetry, as well as DFT/TDDFT calculations. Fluorescence/phosphorescence dual emission were observed for the complex. The ultrafast intramolecular singlet/triplet energy transfer in Pt-1 was confirmed by the transient absorption spectroscopy (kFRET = 2.6 × 10(11) s(-1), ΦFRET = 87.1%) followed by an intersystem crossing (kISC = 1.9 × 10(10) s(-1)), and the triplet state lifetime (τT) is 54.1 µs. The reference complex Pt-4 shows drastically different kinetics with kFRET = 6.9 × 10(10) s(-1), ΦFRET = 81.0%, kISC = 5.83 × 10(9) s(-1), and τT = 147.9 µs. Different singlet oxygen ((1)O2) quantum yields (ΦΔ = 75% and 70%) and triplet state quantum yields (ΦT = 91% and 69%, respectively) were observed for complexes Pt-1 and Pt-4.

7.
Chemistry ; 20(21): 6300-8, 2014 May 19.
Artículo en Inglés | MEDLINE | ID: mdl-24715494

RESUMEN

A series of simple phenothiazine-based dyes, namely, TP, EP, TTP, ETP, and EEP have been developed, in which the thiophene (T), ethylenedioxythiophene (E), their dimers, and mixtures are present to modulate dye aggregation, charge recombination, and dye regeneration for highly efficient dye-sensitized solar cell (DSSC) applications. Devices sensitized by the dyes TP and TTP display high power conversion efficiencies (PCEs) of 8.07 (Jsc = 15.2 mA cm(-2), Voc =0.783 V, fill factor (FF) = 0.679) and 7.87 % (Jsc = 16.1 mA cm(-2), Voc = 0.717 V, FF = 0.681), respectively; these were measured under simulated AM 1.5 sunlight in conjunction with the I(-)/I3(-) redox couple. By replacing the T group with the E unit, EP-based DSSCs had a slightly lower PCE of 7.98 % with a higher short-circuit photocurrent (Jsc) of 16.7 mA cm(-2). The dye ETP, with a mixture of E and T, had an even lower PCE of 5.62 %. Specifically, the cell based on the dye EEP, with a dimer of E, had inferior Jsc and Voc values and corresponded to the lowest PCE of 2.24 %. The results indicate that the photovoltaic performance can be finely modulated through structural engineering of the dyes. The selection of T analogues as donors can not only modulate light absorption and energy levels, but also have an impact on dye aggregation and interfacial charge recombination of electrons at the interface of titania, electrolytes, and/or oxidized dye molecules; this was demonstrated through DFT calculations, electrochemical impedance analysis, and transient photovoltage studies.

8.
J Am Chem Soc ; 135(28): 10566-78, 2013 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-23790008

RESUMEN

Resonance energy transfer (RET) was used for the first time to enhance the visible light absorption of triplet photosensitizers. The intramolecular energy donor (boron-dipyrromethene, Bodipy) and acceptor (iodo-Bodipy) show different absorption bands in visible region, thus the visible absorption was enhanced as compared to the monochromophore triplet photosensitizers (e.g., iodo-Bodipy). Fluorescence quenching and excitation spectra indicate that the singlet energy transfer is efficient for the dyad triplet photosensitizers. Nanosecond time-resolved transient absorption spectroscopy has confirmed that the triplet excited states of the dyads are distributed on both the energy donor and acceptor, which is the result of forward singlet energy transfer from the energy donor to the energy acceptor and in turn the backward triplet energy transfer. This 'ping-pong' energy transfer was never reported for organic molecular arrays, and so it is useful to study the energy level of organic chromophores. The triplet photosensitizers were used for singlet oxygen ((1)O2) mediated photooxidation of 1,5-dihydroxylnaphthalene to produce juglone. The visible light absorption of the new visible light-absorbing triplet photosensitizers are higher than the conventional monochromophore based triplet photosensitizers, as a result, the (1)O2 photosensitizing ability is improved with the new triplet photosensitizers. Triplet-triplet annihilation upconversion with these triplet photosensitizers was also studied. Our results are useful to design the triplet photosensitizers showing strong visible light absorbance and for their applications in photocatalysis and photodynamic therapy.


Asunto(s)
Transferencia Resonante de Energía de Fluorescencia , Luz , Fármacos Fotosensibilizantes/química , Estructura Molecular , Oxidación-Reducción , Procesos Fotoquímicos , Fármacos Fotosensibilizantes/síntesis química , Teoría Cuántica
9.
J Org Chem ; 78(11): 5627-37, 2013 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-23668289

RESUMEN

We used iodo-Bodipy derivatives that show strong absorption of visible light and long-lived triplet excited states as organic catalysts for photoredox catalytic organic reactions. Conventionally most of the photocatalysts are based on the off-the-shelf compounds, usually showing weak absorption in the visible region and short triplet excited state lifetimes. Herein, the organic catalysts are used for two photocatalyzed reactions mediated by singlet oxygen ((1)O2), that is, the aerobic oxidative coupling of amines and the photooxidation of dihydroxylnaphthalenes, which is coupled to the subsequent addition of amines to the naphthoquinones, via C-H functionalization of 1,4-naphthoquinone, to produce N-aryl-2-amino-1,4-naphthoquinones (one-pot reaction), which are anticancer and antibiotic reagents. The photoreactions were substantially accelerated with these new iodo-Bodipy organic photocatalysts compared to that catalyzed with the conventional Ru(II)/Ir(III) complexes, which show weak absorption in the visible region and short-lived triplet excited states. Our results will inspire the design and application of new organic triplet photosensitizers that show strong absorption of visible light and long-lived triplet excited state and the application of these catalysts in photoredox catalytic organic reactions.


Asunto(s)
Aminas/química , Compuestos de Boro/química , Naftalenos/química , Naftoquinonas/síntesis química , Fármacos Fotosensibilizantes/química , Catálisis , Estructura Molecular , Naftoquinonas/química , Oxidación-Reducción , Procesos Fotoquímicos , Oxígeno Singlete/química
10.
Photochem Photobiol Sci ; 12(5): 872-82, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23467514

RESUMEN

A series of ketocoumarin compounds were prepared as heavy atom-free triplet photosensitizers. The photophysical properties of the compounds were studied with steady state and time-resolved spectroscopy. The compounds show absorption in the visible spectral region (molar absorption coefficients are up to ε = 136,000 M(-1) cm(-1) at 448 nm) and long-lived triplet excited states (τT = 199.7 µs) upon visible light photoexcitation. The compounds were used as triplet photosensitizers for singlet oxygen ((1)O2)-mediated photooxidation of 1,5-dihydroxylnaphthalene (DHN) to produce juglone. (1)O2 quantum yields of these compounds were determined in the range of 0.28-0.48. The ketocoumarins were also used as triplet photosensitizers for triplet-triplet annihilation (TTA) upconversion, and upconversion quantum yields up to 11.3% were observed. The results are useful for preparation of heavy atom-free triplet photosensitizers and for their application in photocatalysis and TTA upconversion.

11.
Front Oncol ; 13: 1255112, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37790757

RESUMEN

Background: Ghrelin plays a critical role in regulating energy metabolism and homeostasis. The association between circulating ghrelin levels and gastric cancer has not been systematically analyzed. Objective: This work explored the association between circulating ghrelin levels and gastric cancer. Methods: The literature search for relevant articles published until November 2022 was performed using PubMed, Cochrane Library, EMBASE, and Web of Science with the keywords "ghrelin" and "gastric cancer". Standardized mean differences (SMD) with 95% confidence intervals were used to measure the effectiveness. We assessed pooled data by use of a random-effects model. Results: Of 5,302 identified studies, nine were included (N=3,196 participants). Circulating ghrelin levels were lower in gastric cancer patients (SMD=-0.255, 95%CI: -0.528 to 0.017, P < 0.00001), but with high heterogeneity (I2 = 88.8%). Conclusion: The circulating ghrelin levels in patients with gastric cancer were lower than in controls. However, there was heterogeneity among results; therefore, studies with larger sample sizes are recommended.

12.
Front Immunol ; 14: 1156039, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37325643

RESUMEN

Background: Pre-eclampsia (PE) is a pregnancy complication associated with maternal and fetal morbidity and mortality. Among the potential pathogenesis discussed, inflammation is considered an essential initiator of PE. Previous studies have compared the levels of various inflammatory biomarkers that indicate the existence of PE; however, the relative levels of pro-inflammatory and anti-inflammatory biomarkers and their dynamic changes during PE progression remain unclear. This knowledge is essential to explain the occurrence and progression of the disease. Objective: We aimed to identify the relationship between inflammatory status and PE using inflammatory biomarkers as indicators. We also discussed the underlying mechanism by which inflammatory imbalance contributes to PE by comparing the relative levels of pro-inflammatory and anti-inflammatory biomarkers. Furthermore, we identified additional risk factors for PE. Methods: We reviewed PubMed, Embase, and the Cochrane Library for articles published until 15th September 2022. Original articles that investigated inflammatory biomarkers in PE and normal pregnancy were included. We selected healthy pregnant women as controls. The inflammatory biomarkers in the case and control groups were expressed as standardized mean differences and 95% confidence intervals using a random-effects model. Study quality was assessed using the Newcastle-Ottawa Scale. Publication bias was assessed using Egger's test. Results: Thirteen articles that investigated 2,549 participants were included in this meta-analysis. Patients with PE had significantly higher levels of C-reactive protein (CRP), interleukin (IL)-4, IL-6, IL-8, IL-10, and tumor necrosis factor (TNF) than the controls. CRP and pro-inflammatory cytokine levels were higher than those of anti-inflammatory cytokines. Patients with gestational age > 34 weeks had significantly higher IL-6 and TNF levels. Patients with higher systolic blood pressure had significantly higher IL-8, IL-10, and CRP levels. Conclusion: Inflammatory imbalance is an independent risk factor for PE development. Impairment of the anti-inflammatory system is a crucial initiating factor for PE development. Failed autoregulation, manifested as prolonged exposure to pro-inflammatory cytokines, leads to PE progression. Higher levels of inflammatory biomarkers suggest more severe symptoms, and pregnant women after 34 weeks of gestation are more susceptible to PE.


Asunto(s)
Interleucina-10 , Preeclampsia , Humanos , Femenino , Embarazo , Lactante , Interleucina-6 , Interleucina-8 , Citocinas , Biomarcadores , Factor de Necrosis Tumoral alfa , Proteína C-Reactiva/metabolismo
13.
Inorg Chem ; 51(12): 6517-28, 2012 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-22663151

RESUMEN

A series of novel bis-pyrazole/pyridine complexes, [Zn(2)(HL(1))(2)(µ(2)-SO(4))](2)·EtOH·H(2)O (1), [Co(2)(HL(1))(2)(µ(2)-SO(4))](2)·2DMF·6H(2)O (2), [Zn(4)(HL(1))(4)(µ(4)-SO(4))][OH](2) (3), [Zn(2)(HL(2))(2)(µ(2)-SO(4))]·2H(2)O (4), [Zn(H(2)L(2))(H(2)O)(2)](SO(4))·0.87H(2)O (5) (H(2)L(1) = 2,6-di-(5-phenyl-1H-pyrazol-3-yl)pyridine, H(2)L(2) = 2,6-di-(5-methyl-1H-pyrazol-3-yl)pyridine), were synthesized hydrothermally from the self-assembly of Zn(II) or Co(II) with different types of bipyrazolyl/pyridine derivative ligands. All the complexes were characterized by elemental analysis, IR and UV-vis spectroscopy, powder X-ray diffraction (PXRD), and single-crystal X-ray diffraction. Structural analyses revealed that metal atoms (Zn and Co) in complexes 1-5 are five-coordination modes, forming slightly distorted trigonal bipyramidal geometries. In complexes 1-3, H(2)L(1) ligand connected the two metal centers via the tetradentate fashion, and the same form of connection was found in complex 4 with H(2)L(2) ligand. While in complex 5, H(2)L(2) only connected with one metal center via the tridentate fashion, which was different from those in complexes 1-4. Additionally, there are abundant hydrogen bonding interactions in complexes 1-4. Interestingly, for hydrogen bonding connecting fashions being different, the molecules for the complexes 1 and 4 are held together by the hydrogen bond to form a 1D supramolecular structure, whereas complexes 2 and 3 are a hydrogen bonded dimer. In addition, quantum chemical calculations for 1, 3, and 4, thermal behaviors and photoluminescent properties for 1 and 3-5 were performed and discussed in detail. In the mean time, we found that these complexes had potential catalytic activity for the oxidation reaction of cyclohexane.


Asunto(s)
Compuestos Organometálicos/química , Compuestos Organometálicos/síntesis química , Pirazoles/química , Piridinas/química , Elementos de Transición/química , Catálisis , Cristalografía por Rayos X , Ligandos , Modelos Moleculares , Estructura Molecular , Teoría Cuántica , Espectrofotometría Infrarroja , Espectrofotometría Ultravioleta
14.
Mol Med Rep ; 25(3)2022 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-35039874

RESUMEN

Type­2 diabetes mellitus (T2DM) causes several complications that affect the quality of life and life span of patients. Hyperbaric oxygen therapy (HBOT) has been used to successfully treat several diseases, including carbon monoxide poisoning, ischemia, infections and diabetic foot ulcer, and increases insulin sensitivity in T2DM. The present study aimed to determine the effect of HBOT on ß­cell function and hepatic gluconeogenesis in streptozotocin (STZ)­induced type­2 diabetic mice. To establish a T2DM model, 7­week­old male C57BL/6J mice were fed a high­fat diet (HFD) and injected once daily with low­dose STZ for 3 days after 1­week HFD feeding. At the 14th week, HFD+HBOT and T2DM+HBOT groups received 1­h HBOT (2 ATA; 100% pure O2) daily from 5:00 to 6:00 p.m. for 7 days. The HFD and T2DM groups were maintained under normobaric oxygen conditions and used as controls. During HBOT, the 12­h nocturnal food intake and body weight were measured daily. Moreover, blood glucose was measured by using a tail vein prick and a glucometer. After the final HBO treatment, all mice were sacrificed to conduct molecular biology experiments. Fasting insulin levels of blood samples of sacrificed mice were measured by an ultrasensitive ELISA kit. Pancreas and liver tissues were stained with hematoxylin and eosin, while immunohistochemistry was performed to determine the effects of HBOT on insulin resistance. TUNEL was used to determine the effects of HBOT on ß­cell apoptosis, and immunoblotting was conducted to determine the ß­cell apoptosis pathway. HBOT notably reduced fasting blood glucose and improved insulin sensitivity in T2DM mice. After HBOT, ß­cell area and ß­cell mass in T2DM mice were significantly increased. HBOT significantly decreased the ß­cell apoptotic rate in T2DM mice via the pancreatic Bcl­2/caspase­3/poly(ADP­ribose) polymerase (PARP) apoptosis pathway. Moreover, HBOT improved the morphology of the liver tissue and increased hepatic glycogen storage in T2DM mice. These findings suggested that HBOT ameliorated the insulin sensitivity of T2DM mice by decreasing the ß­cell apoptotic rate via the pancreatic Bcl­2/caspase­3/PARP apoptosis pathway.


Asunto(s)
Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Gluconeogénesis/fisiología , Oxigenoterapia Hiperbárica/métodos , Células Secretoras de Insulina/metabolismo , Hígado/metabolismo , Animales , Apoptosis/fisiología , Glucemia/metabolismo , Western Blotting , Diabetes Mellitus Experimental/sangre , Diabetes Mellitus Experimental/etiología , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/etiología , Dieta Alta en Grasa/efectos adversos , Modelos Animales de Enfermedad , Ayuno/sangre , Prueba de Tolerancia a la Glucosa/métodos , Humanos , Insulina/sangre , Células Secretoras de Insulina/citología , Masculino , Ratones Endogámicos C57BL
15.
Nutrients ; 14(9)2022 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-35565749

RESUMEN

We conducted a systematic review and meta-analysis of randomized clinical trials and pilot trial studies to compare the effectiveness of intermittent fasting (IF) and continuous calorie restriction (CCR) in overweight and obese people. The parameters included body mass index (BMI), body weight, and other metabolism-related indicators. A systematic search in PubMed, Embase, Cochrane Library, and Web of Science was conducted up to January 2022. Standardized mean differences (SMDs) with 95% confidence intervals (CIs) were used to measure the effectiveness. Publication bias was assessed using Egger's test. The stability of the results was evaluated using sensitivity analyses. The significance of body weight change (SMD = -0.21, 95% CI (-0.40, -0.02) p = 0.028) was more significant after IF than CCR. There was no significant difference in BMI (SMD = 0.02, 95% CI (-0.16, 0.20) p = 0.848) between IF and CCR. These findings suggest that IF may be superior to CCR for weight loss in some respects.


Asunto(s)
Restricción Calórica , Ayuno , Peso Corporal , Restricción Calórica/métodos , Humanos , Sobrepeso/terapia , Pérdida de Peso
16.
Surg Obes Relat Dis ; 18(11): 1323-1338, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-36058832

RESUMEN

Obesity impairs cognition. Bariatric surgery can result in substantial weight loss in patients with severe obesity; however, the impact of bariatric surgery on cognitive function remains controversial. To quantify the effect of bariatric surgery on cognition in patients with severe obesity, we performed a meta-analysis of 20 studies retrieved from PubMed, Cochrane, and Embase. Of these, 6 cohort studies found that Roux-en-Y gastric bypass leads to better performance for immediate verbal memory function (standardized mean difference [SMD] = .56; 95% confidence interval [CI]: .30-.82, P < .0001; I2 = 0%) and delayed memory function (SMD = .64; 95% CI: .38-.90, P < .00001; I2 = 0%) during in the short term. Similarly, positive impacts on immediate verbal memory function (SMD = .46; 95% CI: .09-.83, P < .00001) and delayed memory function (SMD = .84; 95% CI: .46-1.22, P < .0001) were identified during a long-term follow-up. The Roux-en-Y gastric bypass group showed no improvements in attention, cognitive speed, and executive function compared with the control obese group. In 14 longitudinal studies (12 single-arm pre-post comparison studies and 2 cohort studies whose control group had no follow-up cognitive data), patients performed better postoperatively than preoperatively in all cognitive domains during repeated assessments. The analysis for the 20 operative groups showed that individuals treated with bariatric surgery had higher scores after repeated assessment of most neuropsychological tests except for animal fluency and letter fluency than baseline scores. These findings suggest that patients with severe obesity may obtain immediate verbal and delayed memory function benefits from Roux-en-Y gastric bypass.


Asunto(s)
Cirugía Bariátrica , Derivación Gástrica , Obesidad Mórbida , Humanos , Obesidad Mórbida/complicaciones , Obesidad Mórbida/cirugía , Resultado del Tratamiento , Obesidad/cirugía , Cognición
17.
Front Endocrinol (Lausanne) ; 12: 708139, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34512548

RESUMEN

Background: Insulin resistance is a metabolic disorder that occurs in type 2 diabetes mellitus and obesity. Genetic factors such as ß3-adrenoceptor polymorphism (Trp64Arg) may be involved in IR and insulin secretion. However, their association is controversial. Therefore, the current meta-analysis was conducted to clarify the relationship between the Trp64Arg and IR. Methods: The literature search was performed in PubMed, Embase, and Web of Science using the keywords "Receptors, Adrenergic, beta-3, Receptors, Adrenergic, Insulin Resistance, Protein-Coupled Receptor Kinase 3" from 2005 to February 7, 2021. We used a random-effects model to calculate the pooled effect size. We conducted subgroup analysis and regression analysis to identify sources of heterogeneity; and Egger's test and funnel plot were used to test publication bias. Finally, we conducted a sensitivity analysis. Results: We included eight papers with 1,586 subjects. There was a positive correlation between Trp64Arg mutation and insulin level (standardized mean difference = 0.20, 95% confidence intervals: 0.00 to 0.39, I2 = 57.6%, p = 0.016). However, there was no association between Trp64Arg and the homeostasis model (HOMA-IR) assessment. Egger's tests showed no publication bias; the sensitivity analysis showed that our results were stable. Regression analysis revealed no source of heterogeneity. Conclusion: Trp64Arg may be associated with IR. European ancestry, obesity, plasma insulin level, and test status may be potential factors affecting the relationship between Trp64Arg and IR.


Asunto(s)
Predisposición Genética a la Enfermedad , Intolerancia a la Glucosa/patología , Resistencia a la Insulina , Polimorfismo Genético , Receptores Adrenérgicos beta/genética , Intolerancia a la Glucosa/etiología , Intolerancia a la Glucosa/metabolismo , Humanos , Pronóstico
18.
Surg Obes Relat Dis ; 17(9): 1655-1672, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-34229937

RESUMEN

Obesity has become an epidemic in several regions globally; it may lead to cardiovascular diseases, diabetes, and dyslipidemia. Despite many therapies, all bariatric procedures fail in some patients. There is a lack of literature comparing treatment effects on specific metabolic indexes. PubMed, Embase, and Cochrane Central Register of Controlled Trials were searched for relevant articles. GeMTC and R software were used to perform a network meta-analysis, draw forest plots, investigate the possibility of statistical heterogeneity, generate I2 statistics, rank probabilities, and evaluate relative effects of surgical procedures. All analyses were based on a Bayesian consistency model. We included 35 randomized controlled trials, comprising 2198 individuals and 13 interventions. For patients with high insulin resistance, single-anastomosis (mini-) gastric bypass (SAGB) and sleeve gastrectomy (SG) may be effective options, with mean differences (95% confidence intervals [CIs]) of -4.45 (-9.04 to -.34) and -4.23 (-6.74 to -2.22), respectively, compared with control groups. For patients with severe dyslipidemia, in addition to SAGB and SG, duodenal switch (DS) may be an effective surgery, with mean differences (95% CIs) of -.97 (-1.39 to -.55), -1.98 (-3.76 to -.19), .53 (.04 to 1.04), and -.94 (-1.66 to -.16) compared with control groups in terms of triglycerides, total cholesterol, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) concentrations, respectively. In adult overweight patients with or without diabetes, SAGB and SG are most effective at ameliorating insulin resistance. SAGB, Roux-en-Y gastric bypass + omentectomy, and DS are useful for reducing triglycerides, total cholesterol, and LDL-C. SG + omentectomy elevates HDL-C concentrations best. Adjustable gastric band and biliopancreatic diversion may not control insulin resistance or dyslipidemia well.


Asunto(s)
Cirugía Bariátrica , Diabetes Mellitus Tipo 2 , Dislipidemias , Resistencia a la Insulina , Adulto , Teorema de Bayes , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/cirugía , Dislipidemias/complicaciones , Humanos , Metaanálisis en Red , Obesidad
19.
Front Oncol ; 10: 390, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32328454

RESUMEN

Background: Radiotherapy is a routine treatment for pelvic cancer patients. While it had been proven effective, gastrointestinal side effects remain a concern, impairing the quality of life. A few studies focused on the effects of hyperbaric oxygen (HBO) treatment to alleviate radiation-induced gastrointestinal complications. This meta-analysis aimed to critically review and summarize existing literature, assessing the effectiveness of HBO therapy for the treatment of radiation-induced gastrointestinal side effects. Methods: Medical literature search was performed with PubMed, Cochrane Library, and EMBASE up to March 14, 2019. Literatures about HBO treatment upon patients undergoing pelvic cancer (endometrial, cervix, rectum, or prostate cancers) radiotherapy were collected, and the effects of HBO treatment on radiotherapy-induced gastrointestinal complications were evaluated. A random-effects model was used to calculate the pooled effect size. Subgroup analyses were performed to search for sources of heterogeneity. Publication bias was detected with Funnel plots and Egger's test. Results: Three different radiotherapy-related gastrointestinal complications, including rectal bleeding, diarrhea, and pain, were analyzed after screening. It was revealed that the improvement rates were considerable in rectal bleeding (0.81, 95% CI: 0.74-0.89) and diarrhea (0.75, 95% CI: 0.61-0.90) and slightly in pain (0.58, 95% CI: 0.38-0.79). Subgroup analysis revealed factors that significantly influenced the heterogeneity of rectal bleeding, diarrhea, and pain (evaluation criteria, follow-up time, and scoring system, respectively). No significant publication bias was detected. Conclusion: HBO treatment might have the potential to alleviate radiotherapy-related gastrointestinal complications, including rectal bleeding, diarrhea, and pain, but more data are needed for further conclusions. Other symptoms were not further analyzed, as the number of studies was insufficient. More large-scale and prospective studies are needed for better evaluation of HBO's therapeutic values.

20.
Artículo en Inglés | MEDLINE | ID: mdl-32082261

RESUMEN

Hyperbaric oxygen (HBO) therapy is a treatment modality useful for diseases. Hypoxia could stimulate the induction of insulin resistance. Therefore, we sought to determine whether hyperbaric oxygen would ameliorate insulin sensitivity by promoting glucose transporter type 4 (GLUT4) expression in muscle and by stimulating UCP1 in brown adipose tissue (BAT) in a streptozocin (STZ)-induced type 2 diabetes mellitus (T2DM) mouse model. Male C57BL/6J mice were treated three times with low-dose of streptozocin (60 mg/kg, i.p.) and were fed with high-fat diets (HFD) to establish the T2DM model. HBO was administered daily as 100% oxygen at 2.0 atmosphere absolute (ATA) for 1 h for a week. We found that HBO significantly reduced blood glucose levels and attenuated insulin resistance in T2DM mice. HBO modulated food intake by influencing the activity of neuropeptide Y (NPY)-positive neurons in the arcuate nucleus (Arc). HBO treatment increased GLUT4 amount and level of phosphorylated Akt (p-Akt) in muscles of T2DM mice whereas this treatment stimulated the phosphorylation of AMPK in muscles of both T2DM and HFD mice. The morphological staining of BAT and the increased expression of uncoupling of protein 1 (UCP1) demonstrated the promotion of metabolism after HBO treatment. These findings suggest that HBO ameliorates insulin sensitivity of T2DM mice by stimulating the Akt signaling pathway and by promoting GLUT4 expression in muscle, and by increasing UCP1 expression in BAT.


Asunto(s)
Tejido Adiposo Pardo/metabolismo , Diabetes Mellitus Tipo 2/terapia , Transportador de Glucosa de Tipo 4/genética , Oxigenoterapia Hiperbárica , Resistencia a la Insulina/genética , Músculo Esquelético/metabolismo , Proteína Desacopladora 1/metabolismo , Animales , Diabetes Mellitus Experimental/complicaciones , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/terapia , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/metabolismo , Transportador de Glucosa de Tipo 4/metabolismo , Resistencia a la Insulina/fisiología , Masculino , Ratones , Ratones Endogámicos C57BL , Oxígeno/metabolismo , Transducción de Señal/genética
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