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1.
Phys Chem Chem Phys ; 26(2): 1077-1085, 2024 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-38098362

RESUMEN

A Cu-Fe bimetallic hydrogel (2-QF-CuFe-G) was constructed through a simple method. The 2-QF-CuFe-G metallohydrogel possesses excellent peroxidase-like activity to catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2. The catalytic mechanism was confirmed by the addition of •OH radical scavenger isopropyl alcohol (IPA), tert-butyl alcohol (TBA) and ˙OH trapping agent terephthalic acid (TA). Remarkably, the resultant blue ox-TMB system can be used to selectively and sensitively detect ascorbic acid (AA) with an LOD of 0.93 µM in the range of 4-36 µM through the colorimetric method. Moreover, the assay based on the 2-QF-CuFe-G metallohydrogel can be successfully applied to detect AA in fresh fruits.

2.
Phys Chem Chem Phys ; 25(27): 18354-18363, 2023 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-37401350

RESUMEN

The construction of smart materials, especially white light emitting (WLE) hydrogels with multi-stimuli responsive properties, has received widespread attention from researchers. In this study, a WLE hydrogel was obtained by the in situ doping of Eu3+ and Tb3+ into a blue emission low molecular weight gelator (MPF). Remarkably, the prepared WLE hydrogel possessed excellent stimuli responsiveness to pH, temperature and chemicals, and could be used as a soft thermometer and a selective sensor for Cu2+. The correlated color temperature of the WLE hydrogel was calculated to be 5063 K, suggesting a potential application in cool white light. Moreover, a series of metallohydrogels with different colors were obtained by modulating the ratio of MPF, Eu3+ and Tb3+ or changing the excitation wavelength, which was an excellent candidate to construct soft materials of a full-color system. Additionally, the WLE hydrogel could be used for constructing anti-counterfeiting materials. Therefore, this study provides a new approach for preparing smart WLE hydrogels with multiple functions.

3.
J Biol Inorg Chem ; 28(2): 205-211, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36652011

RESUMEN

A facile and dual fluorescent chemosensor (named 7-IDF) based on a phenylalanine derivative with an indole group was designed and synthesized. 7-IDF can selectively and sensitively detect Zn2+ via obvious fluorescence enhancement in an aqueous solution. Remarkably, the 7-IDF-Zn complex with blue luminescence has higher selectivity toward cysteine (Cys) and histidine (His) than for other amino acids. Intriguingly, 7-IDF can also be used as an excellent probe to detect Zn2+ in real water samples. Moreover, 7-IDF and 7-IDF-Zn possess excellent biocompatibility and cell permeability, and 7-IDF can consecutively detect Zn2+ and Cys/His in Hela cells through fluorescence imaging experiments. This study suggests that the phenylalanine-based chemosensor possesses great potential applications for the sequential detection of Zn2+ and Cys/His in biosystems.


Asunto(s)
Cisteína , Colorantes Fluorescentes , Humanos , Colorantes Fluorescentes/química , Cisteína/química , Células HeLa , Histidina , Fenilalanina , Espectrometría de Fluorescencia , Zinc
4.
Spectrochim Acta A Mol Biomol Spectrosc ; 271: 120901, 2022 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-35077980

RESUMEN

Metallohydrogels and lanthanide (Ln) fluorescent materials have gained much attention recently. In this study, we designed and synthesized a facile gelator of a phenylalanine-based derivative containing an indazole group (namely IZF). It was found that IZF can self-assemble to form hydrogel at pH ≤ 7. Meanwhile, IZF and Tb3+/Eu3+ can co-assemble to generate IZF-Tb and IZF-Eu metallohydrogels with green and red fluorescence, respectively, at pH 8-11, with excellent multi-stimuli responsiveness. The bimetallic hydrogels of IZF-Tb/Eu exhibit different colors under UV light by adjusting the ratio of Tb3+ and Eu3+. Moreover, white light emission was achieved with IZF-Tb/Eu bimetallic gels through doping carbon dots (CDs) by tailoring the stoichiometric ratio of Ln-complex and CDs. Remarkably, IZF-Tb and IZF-Eu could be used as fluorescent inks with excellent stability. This study indicates that the amino acid derivative-based Ln-metallohydrogels are excellent candidates for constructing information storage and multiple anti-counterfeiting materials.


Asunto(s)
Elementos de la Serie de los Lantanoides , Carbono , Fluorescencia , Elementos de la Serie de los Lantanoides/química , Luz , Fenilalanina
5.
Spectrochim Acta A Mol Biomol Spectrosc ; 250: 119378, 2021 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-33401180

RESUMEN

Supramolecular hydrogels are attracting soft materials with potential applications. In this study, we synthesized a facile gelator (named 2-QF) based on phenylalanine derivative with a Quinoline group. 2-QF can assemble to form hydrogels at room temperature in different colors under low pH values. Moreover, 2-QF was triggered to form a yellow metallohydrogel (2-QF-Zn) at high pH by the coordination between 2-QF and Zn2+. 2-QF-Zn metallohydrogel showed excellent multi-stimuli responsiveness, especially the reversible "on-off" luminescence switching, as induced by base/acid. In addition, at a low concentration, 2-QF can selectively and visibly identify Zn2+ through fluorescence enhancement, and can detect Zn2+ at physiological pH as a chemosensor. Remarkably, 2-QF and 2-QF-Zn exhibited an excellent biocompatibility without cell cytotoxicity, and 2-QF is able to penetrate live HeLa cells and image intracellular Zn2+ by a turn-on fluorescent response, which makes it a potential candidate for biomedical applications.


Asunto(s)
Fenilalanina , Zinc , Colorantes Fluorescentes , Células HeLa , Humanos , Espectrometría de Fluorescencia
6.
Sci Adv ; 6(29): eabb2695, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-32832640

RESUMEN

Here, an integrated cascade nanozyme with a formulation of Pt@PCN222-Mn is developed to eliminate excessive reactive oxygen species (ROS). This nanozyme mimics superoxide dismutase by incorporation of a Mn-[5,10,15,20-tetrakis(4-carboxyphenyl)porphyrinato]-based metal-organic framework compound capable of transforming oxygen radicals to hydrogen peroxide. The second mimicked functionality is that of catalase by incorporation of Pt nanoparticles, which catalyze hydrogen peroxide disproportionation to water and oxygen. Both in vitro and in vivo experimental measurements reveal the synergistic ROS-scavenging capacity of such an integrated cascade nanozyme. Two forms of inflammatory bowel disease (IBD; i.e., ulcerative colitis and Crohn's disease) can be effectively relieved by treatment with the cascade nanozyme. This study not only provides a new method for constructing enzyme-like cascade systems but also illustrates their efficient therapeutic promise in the treatment of in vivo IBDs.

7.
ChemistryOpen ; 8(9): 1172-1175, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31497471

RESUMEN

Design of metal-selective hydrogels is attractive due to potential applications in materials and biological sciences. Although much progress has been made, assembly of both l- and d-amino acid derivatives was less explored for design of metallohydrogels. In this study, we synthesized a facile and small tryptophan derivative containing an imidazole ligand with both l- and d- configurations (denoted as l/d-ImW). Intriguingly, the assembly of (l+d)-ImW gelators was found to selectively form a Ni2+-hydrogel in aqueous medium at room temperature, which shows a rare purple color and exhibits excellent multi-responsiveness. In addition to insights into the gelation mechanism, this study provides a novel approach to the design of metallohydrogels, by the assembly of (l+d)-amino acid derivatives containing both aromatic rings and multiple metal coordination sites.

8.
Chem Commun (Camb) ; 55(46): 6610-6613, 2019 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-31119219

RESUMEN

The X-ray crystal structure of F43Y/T67R myoglobin revealed unique Tyr-heme double cross-links between Tyr43 and the heme 4-vinyl group, which represents a novel post-translational modification of heme proteins. Moreover, with the feature of a distal His-Arg pair, the designed artificial enzyme exhibited a peroxidase activity comparable to that of native peroxidases, such as the most efficient horseradish peroxidase.


Asunto(s)
Materiales Biomiméticos/química , Hemo/química , Mioglobina/química , Tirosina/química , Animales , Arginina/química , Benzotiazoles/química , Guayacol/química , Histidina/química , Peróxido de Hidrógeno/química , Concentración de Iones de Hidrógeno , Cinética , Estructura Molecular , Mutación , Mioglobina/genética , Oxidación-Reducción , Peroxidasas/química , Procesamiento Proteico-Postraduccional , Cachalote , Ácidos Sulfónicos/química
9.
RSC Adv ; 9(8): 4172-4179, 2019 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-35520156

RESUMEN

Human neuroglobin (Ngb) forms an intramolecular disulfide bond between Cys46 and Cys55, with a third Cys120 near the protein surface, which is a promising protein model for heme protein design. In order to protect the free Cys120 and to enhance the protein stability, we herein developed a strategy by designing an additional disulfide bond between Cys120 and Cys15 via A15C mutation. The design was supported by molecular modeling, and the formation of Cys15-Cys120 disulfide bond was confirmed experimentally by ESI-MS analysis. Molecular modeling, UV-Vis and CD spectroscopy showed that the additional disulfide bond caused minimal structural alterations of Ngb. Meanwhile, the disulfide bond of Cys15-Cys120 was found to enhance both Gdn·HCl-induced unfolding stability (increased by ∼0.64 M) and pH-induced unfolding stability (decreased by ∼0.69 pH unit), as compared to those of WT Ngb with a single native disulfide bond of Cys46-Cys55. Moreover, the half denaturation temperature (T m) of A15C Ngb was determined to be higher than 100 °C. In addition, the disulfide bond of Cys15-Cys120 has slight effects on protein function, such as an increase in the rate of O2 release by ∼1.4-fold. This study not only suggests a crucial role of the artificial disulfide in protein stabilization, but also lays the groundwork for further investigation of the structure and function of Ngb, as well as for the design of other functional heme proteins, based on the scaffold of A15C Ngb with an enhanced stability.

10.
Artículo en Chino | WPRIM (Pacífico Occidental) | ID: wpr-775881

RESUMEN

OBJECTIVE@#To compare the effect of electroacupuncture preconditioning with different frequencies on anal pain after milligan-morgan hemorrhoidectomy.@*METHODS@#A total of 120 patients with mixed hemorrhoids were randomly divided into an electroacupuncture group A (dilatational wave, 2 Hz/100 Hz in frequency), an electroacupuncture group B (continuous wave, 2 Hz in frequency) and an electroacupuncture group C (continuous wave, 100 Hz in frequency), 40 cases in each group. Electroacupuncture at Xialiao (BL 34) and Chengshan (BL 57) was applied with tolerant intensity for 30 min before operation in all groups. The number of additional anesthetic drugs in the 3 groups, the visual anal pain score (VAS) and limb activity score at 4, 12, and 24 h after operation, the maximum VAS score within 24 h after surgery and oral dose of aminophenol dihydrocodeine were compared.@*RESULTS@#The number of additional anesthetic drugs in the electroacupuncture group A, the electroacupuncture group B and the electroacupuncture group C were 4, 5, 4 respectively, and there was not statistically significant (>0.05). There was no significant difference in the anal pain VAS score and limb activity score at 4 h after operation among the 3 groups (>0.05), at the 12 h after operation, the VAS scores and limb activity scores in the electroacupunctures group A and B were lower than those in the electroacupuncture group C (<0.05), at 24 h after operation, the VAS score and limb activity score in the electroacupuncture group A were lower than those in the electroacupuncture group B and C (<0.05), the maximum VAS score within 24 h and oral dose of aminophenol dihydrocodeine within 24 h after operation in the electroacupuncture group A were lower than those in the electroacupuncture group B and C (<0.05).@*CONCLUSION@#Different frequency electroacupuncture preconditioning has the effect of alleviating anal pain after milligan-morgan hemorrhoidectomy. The analgesic effect of electroacupuncture with different frequencies is different. The electroacupuncture analgesic effect of 2 Hz /100 Hz dilatational wave is better than 2 Hz and 100 Hz continuous waves.


Asunto(s)
Humanos , Canal Anal , Electroacupuntura , Hemorreoidectomía , Hemorroides , Terapéutica , Dolor Pélvico
11.
Artículo en Chino | WPRIM (Pacífico Occidental) | ID: wpr-776259

RESUMEN

OBJECTIVE@#To investigate the effect of electroacupuncture preconditioning combined with induced urination on urinary retention after milligan-morgan hemorrhoidectomy.@*METHODS@#Eighty patients with mixed hemorrhoids were randomly divided into an electroacupuncture group and a routine group, 40 cases in each group. Anesthesia at Yaoshu (GV 2) was given in the two groups. In the electroacupuncture group, electroacupuncture at Zhongji (CV 3),Guanyuan (CV 4),Pangguangshu (BL 28) and Sanyinjiao (SP 6) was applied with tolerant intensity for 30 min before operation, 2 Hz/100 Hz in frequency. After operation, induced urination was given, namely hot compress of bladder area and sound of hearing water. In the routine group,induced urination was given after operation. The score of the first urination waiting time, the distension of lower abdomen on the evening of the postoperative, the first time urinary volume and incidence of urinary retention were compared between the two groups.@*RESULTS@#The scores of the first urination waiting time after operation and distension of lower abdomen in the evening of the postoperative in the electroacupuncture group were lower than those in the routine group, the first time urinary volume was more than that in the routine group, and the incidence of urinary retention was lower than that in the routine group (5.0% (2/40) vs 22.5% (9/40), all <0.05).@*CONCLUSION@#Electroacupuncture preconditioning combined with induced urination can effectively prevent the incidence of urinary retention after milligan-morgan hemorrhoidectomy.


Asunto(s)
Humanos , Electroacupuntura , Hemorreoidectomía , Hemorroides , Retención Urinaria , Terapéutica , Micción
12.
Dalton Trans ; 47(39): 13788-13791, 2018 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-30252009

RESUMEN

The first La3+-selective metallohydrogel was constructed by using a facile gelator of a phenylalanine derivative containing an imidazole group, N-(1H-imidazol-4-yl)methylidene-l-phenylalanine, namely La-ImF, which exhibits multi-stimuli responsive properties, including to heat, shearing, pH, etc. Various measurements were also carried out to obtain insights into the mechanism of gelation. Moreover, the La-ImF hydrogel can adsorb toxic dyes, making it a potential candidate for sewage treatment.

13.
RSC Adv ; 8(58): 33325-33330, 2018 Sep 24.
Artículo en Inglés | MEDLINE | ID: mdl-35548150

RESUMEN

With the demand nowadays for blue dyes, it is of practical importance to develop a green and efficient biocatalyst for the production of indigo. The design of artificial enzymes has been shown to be attractive in recent years. In a previous study, we engineered a single mutant of sperm whale myoglobin, F43Y Mb, with a novel Tyr-heme cross-link. In this study, we found that it can efficiently catalyze the oxidation of indole to indigo, with a yield as high as 54% compared to the highest yield (∼20%) reported to date in the literature. By further modifying the heme active site, we engineered a double mutant of F43Y/H64D Mb, which exhibited the highest catalytic efficiency (198 M-1 s-1) among the artificial enzymes designed in Mb. Moreover, both F43Y Mb and F43Y/H64D Mb were found to produce the indigo product with a chemoselectivity as high as ∼80%. Based on the reaction system, we also established a convenient and green dyeing method by dyeing a cotton textile during the biosynthesis of indigo, followed by further spraying the concentrated indigo, without the need of strong acids/bases or any reducing agents. The successful application of dyeing a white cotton textile with a blue color further indicates that the designed enzyme and the dyeing method have practical applications in the future.

14.
Artículo en Chino | WPRIM (Pacífico Occidental) | ID: wpr-690783

RESUMEN

<p><b>OBJECTIVE</b>On the basis of western medication, to investigate the effect of electroacupuncture (EA) combined with auricular point sticking therapy for anal pain of mixed hemorrhoid after external excision and internal ligation,so as to explore the method of improving its effect.</p><p><b>METHODS</b>Ninety patients of mixed hemorrhoids who received external excision and internal ligation were randomly assigned into an EA group, an auricular point sticking group and a combined group, 30 cases in each one. All the treatment was applied 30 min before surgery. Electroacupuncture was used at Xialiao (BL 34) and Changqiang (GV 1) in the EA group, once a day. The auricular points were bilateral shenmen (TF), pizhixia (AT), jiaogan (AH) and gangmen (HX) in the auricular point sticking group, pressing 3-6 times every day, once 3-5 min. EA and auricular point sticking therapy were applied in the combined group. When the visual analogue scale (VAS) score was above 6, aminophenol dihydrocodeine was applied in the three groups. The scores of anal pain VAS and limb activity at the 4th, 12th, 24th, 48th, 72th hours after operation were compared among the three groups, as well as the maximum scores of VAS in 24 hours (T24max VAS) of 1-3 days after operation, the total dose of aminophenol dihydrocodeine 72 h after operation.</p><p><b>RESULTS</b>The VAS and limb activity scores at all the time points after operation, the T24max VAS on the 1st, 2nd and 3rd days after operation and the dose of aminophenol dihydrocodeine in the combined group were better than those in the EA and auricular point sticking groups (all <0.05). The VAS and limb activity scores at 4, 12, 24 h after operation and T24max VAS on the 1st day after operation in the EA group were lower than those in the auricularpoint sticking group (all <0.05). The VAS and limb activity scores at 48, 72 h after operation, and the T24max VAS on the 2nd and 3rd days in the auricular point sticking group were lower than those in the EA group (all <0.05).</p><p><b>CONCLUSION</b>EA combined with auricular point sticking therapy are better than simple EA and auricular point sticking therapy for anal pain of mixed hemorrhoid after external excision and internal ligation. The analgesic effect of EA is rapider, and the effect of auricular point sticking therapy is longer. The combination of the two methods own coordination effect.</p>

15.
Artículo en Chino | WPRIM (Pacífico Occidental) | ID: wpr-329122

RESUMEN

<p><b>OBJECTIVE</b>To observe the differences in the therapeutic effects on chronic perianal eczema between auricular point sticking therapy and auricular sticking pseudo-press therapy on the basis of the treatment with western medication.</p><p><b>METHODS</b>Ninety patients were randomized into an auricular therapy group and an auricular pseudo-press therapy group (pseudo group), 45 cases in each one. The western medication was used in both of the groups. In the auricular therapy group, the auricular sticking method with semen vaccariae was added at Fengxi (SF), Shenshangxian (TG), Duipingjian (AT), Fei (CO), Pi (CO), Gangmen (HX). The patients were advised to press each auricular point every day. In the pseudo group, the plaster was applied to the same auricular points without semen vaccariae used and pressing manipulation given. The auricular sticking therapy was used once every three days in the two groups. The treatment for 2 weeks was as one session and one or two sessions of treatment were given accordingly. The severity of perianal itching, the area of skin lesion, the form of skin lesion and the score of dermatology life quality index (DLQI) and the clinical therapeutic effects were compared before and after treatment in the two groups. The adverse reaction and recurrence rate in 1-year follow-up visit were observed during treatment.</p><p><b>RESULTS</b>After treatment, the itching degree, the area of skin lesion, the form of skin lesion and DLQI score were all reduced apparently as compared with those before treatment in the patients of the two groups (all<0.05). The results in the auricular sticking therapy group were better than those in the pseudo group (all<0.05). The curative and markedly effective rate and the total effective rate in the auricular sticking therapy group were apparently better than those in the pseudo group[52.3% (23/44) vs 19.0% (8/42), 97.7% (43/44) vs 76.2% (32/42), both<0.05]. The recurrence rate in the auricular sticking therapy group was lower apparently than that in the pseudo group[7.0% (3/43) vs 37.5% (12/32),<0.05]. No severe adverse reactions were found during the treatment in the two groups.</p><p><b>CONCLUSIONS</b>The auricular sticking therapy combined with western medication effectively release itching in chronic perianal eczema and local skin lesions, improve the living quality and reduce recurrence rate.</p>

16.
Artículo en Chino | WPRIM (Pacífico Occidental) | ID: wpr-352647

RESUMEN

<p><b>OBJECTIVE</b>To compare the difference in the clinical efficacy on anal pendant expansion after PPH (procedure for prolapse and hemorrhoids) of mixed hemorrhoid between acupuncture at Xialiao (BL 34) and Chang-qiang (GV 1) and oral administration of diosmin.</p><p><b>METHODS</b>Sixty cases of mixed hemorrhoids after PPH were randomized into an observation group and a control group, 30 cases in each one. In the observation group, since the 1st day, acupuncture had been applied to Xialiao (BL 34) and Changqiang (GV 1). The needles were retained for 30 min afterarrival, and the treatment was given once a day, totally for 7 days. In the control group, diosmin tablets had been prescribed for oral administration since the 1st day, 0.9 g each time, twice a day, totally for 7 days. The degree, persistent time and the pain score of anal pendant expansion were compared on the 1st, 2nd, 3rd and 7th days after PPH between the two groups and the efficacy was evaluated.</p><p><b>RESULTS</b>On the 1st day after PPH, the diffe-rences in the scores of the degree and persistent time of anal pendant expansion were not significant statistically between the two groups (all>0.05), but the pain score in the observation group was lower than that in the control group (<0.05) and lower than that before treatment (<0.05). On the 2nd, 3rd and 7th days after PPH, the degree and persistent time of anal pendant expansion and pain score in the two groups were all lower than those before treatment (all<0.05). The results in the observation group were better than those in the control group (all<0.05). At the end of treatment (on the 7th day after PPH), the total effective rate in the observation group was higher than that in the control group[90.0% (27/30) vs 83.3% (25/30),<0.05].</p><p><b>CONCLUSIONS</b>Acupuncture at Xialiao (BL 34) and Changqiang (GV 1) achieves the superior efficacy on anal pendant expansion after PPH of mixed hemorrhoids as compared with diosmin tablets.</p>

17.
Chinese Journal of Dermatology ; (12): 356-358, 2016.
Artículo en Chino | WPRIM (Pacífico Occidental) | ID: wpr-488828

RESUMEN

Objective To investigate the serovar distribution of Chlamydia trachomatis (Ct) isolated from male patients with urethritis in sexually transmitted disease (STD) clinic.Methods Urine specimens were collected from male patients with urethritis in STD clinic at Hospital of Dermatology,Chinese Academy of Medical Sciences between January 2013 and December 2013.Fluorescence-based quantitative PCR was performed to detect Ct DNA in these specimens.DNA was extracted from Ct-positive urine specimens,and nested PCR was conducted to amplify the VS1-VS2 regions of the outer membrane protein A (ompA) gene,followed by gene sequencing.The resulting sequences were aligned to reference sequences by the DNAStar5.0 software to determine Ct serovars.Results A total of 432 urine specimens were collected,and 33.1% (143/432) of them were positive for Ct.The VS1-VS2 regions of the ompA gene were amplified from 127 out of the 143 Ct-positive specimens,but not from the other 16 specimens.Nine serovars were identified by gene sequencing among the 127 specimens,including serovar E (29 strains,22.83%),F (28 strains,22.05%),D (19 strains,14.96%),G (16 strains,12.60%),J (16 strains,12.60%),K (8 strains,6.30%),H (5 strains,3.94%),I (3 strains,2.36%) and B (3 strains,2.36%),and Ct serovars E,F,D,J and G accounted for 85.02% among all the strains.Synonymous mutations were identified in 14 out of the 127 strains when compared with reference strains.Conclusions E,F,D and G serovars were the main Ct serovars in male patients with urethritis in STD clinic.The proportion of Ct serovar E strain was decreased,but that of serovar J strain was increased compared with 20 years ago.

18.
Zhonghua Yi Xue Za Zhi ; 93(31): 2463-6, 2013 Aug 20.
Artículo en Chino | MEDLINE | ID: mdl-24300265

RESUMEN

OBJECTIVE: To analyze the relationship between gestational age and apparent diffusion coefficient (ADC) values in different regions of fetal brain from middle to late trimester. METHODS: DW images performed in 70 singleton non-sedated fetuses with questionably abnormal results on sonography and normal fetal MR imaging results were retrospectively reviewed. The median gestational age was 32.4 weeks (range, 24-38).With the formula of ADC = ln (S600/S0)/(B0-B600), the mean ADC values were obtained for fetal parietal white matter (WM), frontal WM, temporal WM, occipital WM, pons, cerebellum, basal ganglia and thalamus. The relationship of mean ADC values in different regions with gestational age was analyzed with linear regression. RESULTS: The mean ADC values were 1.77 ± 0.32 mm(2)/s (SD) in fetal parietal white matter (WM), 1.71 ± 0.32 mm(2)/s in occipital WM, 1.31 ± 0.18 mm(2)/s in thalamus, 1.34 ± 0.15 mm(2)/s in basal ganglia. And the mean ADC values in cerebellum, pons, frontal WM and temporal WM were 1.17 ± 0.16, 1.41 ± 0.18, 1.87 ± 0.18 and 1.74 ± 0.19 mm(2)/s respectively. A significant negative correlation between ADC values and gestational age was found for parietal WM, occipital WM, pons, cerebellum, basal ganglia and thalamus (P < 0.05). Frontal WM ADC (P > 0.05) and temporal WM ADC (P = 0.05) did not significantly change with gestational age whereas only a downward trend was present. The correlation coefficient (r) and coefficient of regression (b) were 0.420 and -0.045 in parietal WM; 0.470 and -0.052 in occipital WM; 0.370 and -0.027 in cerebellum; 0.027 and -0.020 in pons; 0.320 and -0.027 in thalamus; 0.300 and -0.021 in basal ganglia. The mean ADC values peaked in frontal WM and lowest in pons. The mean ADC values in white matter were higher than those in deep gray nuclei, cerebellum and pons.With the development of fetal brain,ADC values declined the fastest in cerebellum and occipital WM, followed by basal ganglia and thalamus. CONCLUSION: Regional differences in non-sedated fetal brain ADC values and their evolutions with gestational age are likely to reflect variations in brain maturation.


Asunto(s)
Encéfalo/embriología , Imagen de Difusión por Resonancia Magnética/métodos , Edad Gestacional , Femenino , Humanos , Embarazo , Segundo Trimestre del Embarazo , Tercer Trimestre del Embarazo
19.
Bioorg Med Chem Lett ; 21(19): 5818-21, 2011 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-21855336

RESUMEN

Aggregation and fibril formation of ß-amyloid peptides (Aß) is the key event in the pathogenesis of Alzheimer's disease. Many efforts have been made on the development of effective inhibitors to prevent Aß fibril formation or disassemble the preformed Aß fibrils. Peptide inhibitors with sequences homologous to the hydrophobic segments of Aß can alter the aggregation pathway of Aß, together with decrease of the cell toxicity. In this study, the conjugate of ferrocenoyl (Fc) with pentapeptide KLVFF (Fc-KLVFF), was synthesized by HBTU/HOBt protocol in solution. The inhibitory effect of Fc-KLVFF on Aß(1-42) fibril formation was evaluated by thioflavin T fluorescence assay, and confirmed by atomic force microscopy (AFM) and transmission electron microscopy (TEM) analyses. Fc-KLVFF shows high inhibitory effect towards the fibril formation of Aß(1-42). Additionally, the attachment of ferrocenoyl moiety onto peptides allows us to investigate the interaction between the inhibitor and Aß(1-42) in real-time by electrochemical method. As expected, tethering of ferrocenoyl moiety onto pentapeptide shows improved lipophilicity and significant resistance towards proteolytic degradation compared to its parent peptide.


Asunto(s)
Enfermedad de Alzheimer/tratamiento farmacológico , Péptidos beta-Amiloides/química , Péptidos beta-Amiloides/metabolismo , Diseño de Fármacos , Compuestos Férricos/síntesis química , Compuestos Férricos/farmacología , Nootrópicos/síntesis química , Nootrópicos/farmacología , Oligopéptidos/síntesis química , Oligopéptidos/farmacología , Fragmentos de Péptidos/química , Fragmentos de Péptidos/metabolismo , Enfermedad de Alzheimer/patología , Benzotiazoles , Evaluación Preclínica de Medicamentos , Técnicas Electroquímicas , Compuestos Férricos/química , Microscopía de Fuerza Atómica , Microscopía Electrónica de Transmisión , Terapia Molecular Dirigida , Nootrópicos/química , Oligopéptidos/química , Oxidación-Reducción , Péptidos/química , Solubilidad , Tiazoles/química
20.
Analyst ; 136(19): 4003-7, 2011 Oct 07.
Artículo en Inglés | MEDLINE | ID: mdl-21853196

RESUMEN

This paper describes the fabrication and application of a complex electrode--Nafion film coating ferrocenylalkanethiol (FcC(11)SH) and encapsulated glucose oxidase (GOD) on a gold electrode. FcC(11)SH is employed as a mediator enabling the electron transfer between GOD and the electrode, GOD is encapsulated in polyacrylamide gel to improve the stability of the enzyme, and the Nafion film is coated on the modified electrode to eliminate interferents such as ascorbic acid, uric acid and acetaminophen in amperometric glucose detection. It is noticed that such a complex electrode exhibits excellent catalytic activity for glucose oxidation, and preserves the native structure of GOD and therefore its enzymatic activity. The encapsulated GOD retains more than 80% of its original biocatalytic activity even after 24 days, much longer than that of naked GOD molecules attached directly to the electrode. The oxidation peak current at the modified electrode shows a linear relationship with the glucose concentration in the range from 0.05 to 20 mM with a detection limit of 2.4 µM. In addition, the electrode displays a rapid response and good reproducibility for glucose detection, and has been successfully employed for glucose detection in blood plasma samples.


Asunto(s)
Materiales Biocompatibles Revestidos/química , Compuestos Ferrosos/química , Polímeros de Fluorocarbono/química , Glucosa Oxidasa/metabolismo , Glucosa/análisis , Compuestos de Sulfhidrilo/química , Biocatálisis , Electrodos , Compuestos Ferrosos/metabolismo , Polímeros de Fluorocarbono/metabolismo , Glucosa/metabolismo , Glucosa Oxidasa/química , Membranas Artificiales , Compuestos de Sulfhidrilo/metabolismo , Propiedades de Superficie
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