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1.
Mol Ther ; 2024 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-38822524

RESUMO

Dysregulated T cell activation underpins the immunopathology of rheumatoid arthritis (RA), yet the machineries that orchestrate T cell effector program remain incompletely understood. Herein, we leveraged bulk and single-cell RNA sequencing data from RA patients and validated protein disulfide isomerase family A member 3 (PDIA3) as a potential therapeutic target. PDIA3 is remarkably upregulated in pathogenic CD4 T cells derived from RA patients and positively correlates with C-reactive protein level and disease activity score 28. Pharmacological inhibition or genetic ablation of PDIA3 alleviates RA-associated articular pathology and autoimmune responses. Mechanistically, T cell receptor signaling triggers intracellular calcium flux to activate NFAT1, a process that is further potentiated by Wnt5a under RA settings. Activated NFAT1 then directly binds to the Pdia3 promoter to enhance the expression of PDIA3, which complexes with STAT1 or PKM2 to facilitate their nuclear import for transcribing T helper 1 (Th1) and Th17 lineage-related genes, respectively. This non-canonical regulatory mechanism likely occurs under pathological conditions, as PDIA3 could only be highly induced following aberrant external stimuli. Together, our data support that targeting PDIA3 is a vital strategy to mitigate autoimmune diseases, such as RA, in clinical settings.

2.
Appl Environ Microbiol ; 87(10)2021 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-33712420

RESUMO

The emergence and spread of extended-spectrum ß-lactamases (ESBLs), metallo-ß-lactamases (MBLs), or variant low-affinity penicillin-binding proteins (PBPs) pose a major threat to our ability to treat bacterial infection using ß-lactam antibiotics. Although combinations of ß-lactamase inhibitors with ß-lactam agents have been clinically successful, there are no MBL inhibitors in current therapeutic use. Furthermore, recent clinical use of new-generation cephalosporins targeting PBP2a, an altered PBP, has led to the emergence of resistance to these antimicrobial agents. Previous work shows that natural polyphenols such as cranberry-extracted proanthocyanidins (cPAC) can potentiate non-ß-lactam antibiotics against Gram-negative bacteria. This study extends beyond previous work by investigating the in vitro effect of cPAC in overcoming ESBL-, MBL-, and PBP2a-mediated ß-lactam resistance. The results show that cPAC exhibit variable potentiation of different ß-lactams against ß-lactam-resistant Enterobacteriaceae clinical isolates as well as ESBL- and MBL-producing E. coli We also discovered that cPAC have broad-spectrum inhibitory properties in vitro on the activity of different classes of ß-lactamases, including CTX-M3 ESBL and IMP-1 MBL. Furthermore, we observe that cPAC selectively potentiate oxacillin and carbenicillin against methicillin-resistant but not methicillin-sensitive staphylococci, suggesting that cPAC also interfere with PBP2a-mediated resistance. This study motivates the need for future work to identify the most bioactive compounds in cPAC and to evaluate their antibiotic-potentiating efficacy in vivoIMPORTANCE The emergence of ß-lactam-resistant Enterobacteriaceae and staphylococci compromises the effectiveness of ß-lactam-based therapy. By acquisition of ESBLs, MBLs, or PBPs, it is highly likely that bacteria may become completely resistant to the most effective ß-lactam agents in the near future. In this study, we described a natural extract rich in proanthocyanidins which exerts adjuvant properties by interfering with two different resistance mechanisms. By their broad-spectrum inhibitory ability, cranberry-extracted proanthocyanidins could have the potential to enhance the effectiveness of existing ß-lactam agents.


Assuntos
Ampicilina/farmacologia , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Cefotaxima/farmacologia , Proantocianidinas/farmacologia , Vaccinium macrocarpon , Bactérias/crescimento & desenvolvimento , Sinergismo Farmacológico , Resistência beta-Lactâmica/efeitos dos fármacos
3.
Electrophoresis ; 41(10-11): 802-810, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32107787

RESUMO

Due to its versatile applications in biotechnology, ion current rectification (ICR), which arises from the asymmetric nature of the ion transport in a nanochannel, has drawn much attention, recently. Here, the ICR behavior of a pH-regulated nanochannel comprising two series connected cylindrical nanochannels of different radii is examined theoretically, focusing on the influences of the radii ratio, the length ratio, the bulk concentration, and the solution pH. The results of numerical simulation reveal that the rectification factor exhibits a local maximum with respect to both the radii ratio and the length ratio. The values of the radii ratio and the length ratio at which the local maximum in the rectification factor occur depend upon the level of the bulk salt concentration. The rectification factor also shows a local maximum as the solution pH varies. Among the factors examined, the solution pH influences the ICR behavior of the nanochannel most significantly.


Assuntos
Íons/química , Nanotecnologia/métodos , Técnicas Eletroquímicas , Concentração de Íons de Hidrogênio , Modelos Químicos , Nanoestruturas
4.
J Biomed Opt ; 29(Suppl 1): S11514, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38169937

RESUMO

Significance: A Fabry-Perot (FP) polymer film sensor can be used to detect acoustic waves in a photoacoustic endoscope (PAE) if the dimensions can be adequately scaled down in size. Current FP sensors have limitations in size, sensitivity, and array configurability. Aim: We aim to characterize and demonstrate the imaging performance of a miniature FP sensor to evaluate the effects of reduced size and finite dimensions. Approach: A transfer matrix model was developed to characterize the frequency response of a multilayer miniature FP sensor. An analytical model was derived to describe the effects of a substrate with finite thickness. Finite-element analysis was performed to characterize the temporal response of a sensor with finite dimensions. Miniature 2×2 mm2 FP sensors were designed and fabricated using gold films as reflective mirrors on either side of a parylene C film deposited on a glass wafer. A single-wavelength laser was used to interrogate the sensor using illumination delivered by fiber subprobes. Imaging phantoms were used to verify FP sensor performance, and in vivo images of blood vessels were collected from a live mouse. Results: The finite thickness substrate of the FP sensor resulted in echoes in the time domain signal that could be removed by back filtering. The substrate acted as a filter in the frequency domain. The finite lateral sensor dimensions produced side waves that could be eliminated by surface averaging using an interrogation beam with adequate diameter. The fabricated FP sensor produced a noise-equivalent pressure = 0.76 kPa, bandwidth of 16.6 MHz, a spectral full-width at-half-maximum = 0.2886 nm, and quality factor Q=2694. Photoacoustic images were collected from phantoms and blood vessels in a live mouse. Conclusions: A miniature wafer-based FP sensor design has been demonstrated with scaled down form factor for future use in PAE.


Assuntos
Acústica , Polímeros , Animais , Camundongos , Polímeros/química , Análise Espectral , Imagens de Fantasmas , Endoscopia Gastrointestinal
5.
Photoacoustics ; 31: 100519, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37362870

RESUMO

In our previous study, we demonstrated the feasibility of using an all-optical interstitial photoacoustic (PA) needle sensing probe for quantitative study of tissue architectures with PA spectral analysis (PASA). In this work, we integrated the optical components into an 18 G steel needle sheath for clinical translation. The dimensions of the needle probe are identical to those of a core biopsy probe and are fully compatible with standard procedures such as prostate biopsy. To our knowledge, this is the first interstitial PA probe that can acquire signals with sufficient temporal length for statistics-based PASA. We treated the inner surface of the steel needle sheath and successfully suppressed the vibrational PA signals generated at the surface. Purposed at boosting the measurement sensitivity and extending sensing volume, we upgraded the Fabry-Pérot hydrophone with a plano-concave structure. The performance of the translational needle PA sensing probe was examined with phantoms containing microspheres. The trend of the linear spectral slopes shows negatively correlated to the microsphere dimensions while the midband-fits are positively correlated to microsphere diameters and concentrations. The PASA quantifications show the ability to differentiate microspheres with varied dimensions.

6.
ACS Appl Mater Interfaces ; 15(17): 21008-21015, 2023 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-37069786

RESUMO

Polymers with broad infrared emission and negligible solar absorption have been identified as promising radiative cooling materials to offer a sustainable and energy-saving venue. Although practical applications desire color for visual appearance, the current coloration strategies of polymer-based radiative cooling materials are constrained by material, cost, and scalability. Here, we demonstrate a universally applicable coloration strategy for polymer-based radiative cooling materials by nanoimprinting. By modulating light interference with periodic structures on polymer surfaces, specular colors can be induced while maintaining the hemispheric optical responses of radiative cooling polymers. The retrofit strategy is exemplified by four different polymer films with a minimum impact on optical responses compared to the pristine films. Polymer films feature low solar absorption of 1.7-3.7%, and daytime sub-ambient cooling is exemplified in the field test. The durability of radiative cooling and color are further validated by dynamic spectral analysis. Finally, the potential roll-to-roll manufacturing empowers a scalable, low-cost, and easy-retrofitting solution for colored radiative cooling films.

7.
Nanomaterials (Basel) ; 12(22)2022 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-36432243

RESUMO

In this study, blue perovskite quantum dots (PQDs) were prepared using didodecyldimethylammonium bromide (DDAB), which can passivate surface defects caused by the loss of surface ligands and reduce particle size distribution. After the passivation of DDAB, blue CsPbClxBr3-x PQDs dispersed in n-octane produced a more compact and uniform PQD thin film than the non-passivated ones. The resulting device showed a stabile lifetime, and an EL peak of 470 nm and a maximum EQE of 1.63% were obtained at an operating voltage of 2.6 V and a current density of 0.34 mA/cm2. This work aims to provide a simple method to prepare blue-emitting PQDs and high-performance PQD-based light-emitting devices.

8.
Photoacoustics ; 28: 100418, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36386297

RESUMO

In our previous studies, we demonstrated the ability of an interstitial all-optical needle photoacoustic (PA) sensing probe and PA spectral analysis (PASA) to assess the aggressiveness of prostate cancer. In this clinical translation investigation, we integrated the optical components of the needle PA sensing probe into a 18G steel needle. The translational needle PA sensing probe was evaluated using intact human prostates in a simulated ultrasound-guided transperineal prostate biopsy. PA signals were acquired at 1220 nm, 1370 nm, 800 nm and 266 nm at each interstitial measurement location and quantified by PASA within the frequency range of 8-28 MHz. The measurement locations were stained for establishing spatial correlations between the quantitative measurements and the histological diagnosing. Most of the quantitative PA assessments reveal statistically significant differences between the benign and cancerous regions. Multivariate analysis combining the PASA quantifications shows an accuracy close to 90% in differentiating the benign and cancerous regions in the prostates.

9.
J Colloid Interface Sci ; 588: 94-100, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33388590

RESUMO

A continuum model is adopted to describe the electrokinetic behavior of a pH-regulated cylindrical nanopore, the surface of which has charge-regulated carboxyl groups. We focus on the influences of the permittivity of the nanopore material, nanopore size, salt concentration, and solution pH on this behavior, and the underlying mechanisms. The influence of the nanopore permittivity becomes significant when a nanopore is shorter than ca. 50 nm. It is interesting to observe that if it is longer than ca. 100 nm, the nanopore conductance decreases with increasing permittivity. If it is sufficiently short, the conductance increases with increasing permittivity. If the nanopore length takes a medium level, the conductance is insensitive to the variation in the permittivity. For a short nanopore (~20 nm), the conductivity increases with increasing permittivity. However, if pH is sufficiently high, it becomes insensitive to permittivity. Although the larger the permittivity the greater the conductivity, in general, this effect becomes insignificant when the bulk salt concentration is sufficiently high, implying that the effect of membrane polarization is important only if the bulk salt concentration is sufficiently low.

10.
World J Clin Cases ; 8(13): 2749-2757, 2020 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-32742985

RESUMO

BACKGROUND: Osteonecrosis of the femoral head (ONFH) is a destructive condition most commonly affecting young and middle-aged patients. The leading consequence of ONFH is often a significant articular disability. Effective joint-preserving surgical treatments are urgently needed for patients with early stage ONFH when outcomes of treatment are in general better than the advanced stage disease. AIM: To introduce a new surgery procedure called percutaneous expanded core decompression and mixed bone graft technique, which is a new way of joint-preserving surgical treatments. METHODS: The clinical data of 6 patients with ONFH diagnosed and treated with the procedure called percutaneous expanded core decompression and mixed bone graft technique at The First Hospital of Qiqihar from March 2013 to August 2019 were retrospectively analyzed; the follow-up ended in December 2019. RESULTS: There were 6 male patients with an average age of 43 years in our study. Gratifying results have been obtained from the comparison of Harris hip score, visual analogue scale, and imaging examination before and after operation. CONCLUSION: This new modified technique is simple, safe, and reliable. No serious perioperative complications were observed in our cases. Advantages of the single blade expandable reamer are obvious. The adjuvant substance is inexpensive and easy to obtain. Thus, this technique is an effective joint-preserving surgical treatment for patients with early stage of ONFH.

11.
Bioorg Med Chem ; 17(8): 3126-9, 2009 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-19329326

RESUMO

A synthetic route to (1S,2S,3R,5S)-3-(6-amino-9H-purin-9-yl)-5-fluorocyclopentane-1,2-diol (that is, the 4'-fluoro derivative of 4'-deoxy-5'-noraristeromycin, 3) is described via a fluorinated cyclopentanol, which is in contrast to existing schemes where fluorination occurred once the purine ring was present. Compound 3 was assayed versus a number of viruses. A favorable response was observed towards measles (IC(50) of 1.2 microg/mL in the neutral red assay and 14 microg/mL by the visual assay) but this was accompanied by cytotoxicity in the CV-1 host cells (21-36 microg/mL). Among the viruses unaffected by 3 were human cytomegalovirus and the poxviruses (vaccinia and cowpox), which are three viruses that were inhibited by the 4',4'-difluoro analog of 3 (that is, 2).


Assuntos
Adenosina/análogos & derivados , Antivirais/química , Antivirais/farmacologia , Citomegalovirus/efeitos dos fármacos , Poxviridae/efeitos dos fármacos , Adenosina/síntese química , Adenosina/química , Adenosina/farmacologia , Antivirais/síntese química , Linhagem Celular , Citomegalovirus/crescimento & desenvolvimento , Humanos , Hidrocarbonetos Fluorados/síntese química , Hidrocarbonetos Fluorados/química , Hidrocarbonetos Fluorados/farmacologia , Concentração Inibidora 50 , Espectroscopia de Ressonância Magnética , Poxviridae/crescimento & desenvolvimento , Estereoisomerismo , Relação Estrutura-Atividade
12.
Biosci Rep ; 39(4)2019 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-30962270

RESUMO

Background: The present study aimed to evaluate serum 25-hydroxy vitamin D (25(OH) D) levels in Chinese patients with idiopathic benign paroxysmal positional vertigo (BPPV) and to investigate the possible relationship between the occurrence and recurrence of idiopathic BPPV and low 25(OH) D levels. Methods: Between 1 January 2017 and 31 May, 2018, consecutively older patients (age, older than 50 years) with idiopathic BPPV were recruited in the present study. For each patient, 2:1 sex and age matched healthy people were assigned as the control group. The influence of 25(OH) D levels on BPPV and recurrent BPPV were performed by binary logistic regression analysis. Results: In the present study, 174 patients with BPPV and 348 controls were included. The serum levels of 25(OH) D in those patients were lower than in those controls (P<0.001). One hundred eight patients were found to have vitamin D deficiency; thus, the prevalence was 62.1%, which was higher than that in the controls (42.8%). The data showed that patients with recurrent BPPV (N = 31) had lower serum levels of 25(OH) D compared with those who were not (11.2 ng/ml [interquartile range, 7.2-20.8 ng/ml] vs 18.7 ng/ml [14.2-24.8 ng/ml]). The regression analyses demonstrated that vitamin D deficiency was associated with BPPV and recurrent BPPV with an odds ratio of 2.15 (95% confidence interval [CI], 1.30-4.32; P=0.006) and 5.16 (95% CI, 1.00-34.12; P=0.05). Conclusion: Decreased serum levels of 25(OH)D were associated with the occurrence and recurrence of BPPV in a Chinese population, independent of other baseline markers.


Assuntos
Vertigem Posicional Paroxística Benigna/sangue , Vitamina D/análogos & derivados , Idoso , Povo Asiático , Vertigem Posicional Paroxística Benigna/epidemiologia , Vertigem Posicional Paroxística Benigna/etiologia , Biomarcadores/sangue , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Curva ROC , Fatores de Risco , Vitamina D/sangue , Deficiência de Vitamina D/sangue , Deficiência de Vitamina D/epidemiologia
13.
Chin J Traumatol ; 10(1): 3-9, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17229343

RESUMO

OBJECTIVE: To observe the distribution of the nerve fibers in the bone tissue and the entry points of these fibers into the bone. METHODS: The adult tibia was used for the ground sections which were afterwards made into the slice sections by decalcification in ethylenediamine tetraacetic acid (EDTA). The ground sections were stained in silver and the slice sections were stained in silver and haematoxylin and eosin (HE) respectively. Then, the samples of the transmission electron microscope and the atomic force microscope were made and observed. RESULTS: In the human long bone tissue, many nerve fibers were distributed in the membrane, cortical bone, cancellous bone and marrow. The nerve fibers entered the bone from the nutrient foramen, and passed through the nutrient canal, Haversian's canal and Volkmann's canal, and finally into the bone marrow. In the nutrient canal, the nerve fibers, mainly the medullary nerve fibers, followed the blood vessel into the bone. In the cortical bone, the nerve fibers also followed the blood vessels and were mainly distributed along Haversian's canal and Volkmann's canal. In the bone trabecular and bone marrow, there were many nerve fiber endings arranged around the blood vessels, mainly around the tunica media of medium-size arteries in the marrow and around capillary blood vessels, and a few scattered in the bone marrow. There were sporadic nerve endings in epiphyseal plate and no nerve fibers permeated epiphysis to diaphysis. No distribution of nerve fibers could be found in cartilaginous part. CONCLUSIONS: There are many nerve fibers in bone and the nerve passageway is nutrient foramen, Volkman's canal, Haversian's canal and bone marrow.


Assuntos
Fibras Nervosas , Tíbia/anatomia & histologia , Adulto , Humanos , Microscopia de Força Atômica , Microscopia Confocal , Microscopia Eletrônica de Varredura , Fibras Nervosas/ultraestrutura , Coloração e Rotulagem , Tíbia/inervação , Tíbia/ultraestrutura
14.
J Phys Chem B ; 109(28): 13510-4, 2005 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-16852689

RESUMO

Sodium salts of poly(oxypropylene)-trimellitic amido acid (POP-amido acid), prepared from the reaction of POP-diamines and trimellitic anhydride, were found to self-assemble into orderly molecular bundles. The POP-amido acid has a symmetrical structure consisting of a hydrophobic POP middle block (2000 g/mol) and four symmetrical carboxyl end groups. By dissolving in water and evaporating on a polyether sulfone film, the POP-amido acid molecules self-assembled into a unique array with average dimensions of 7-13 nm in width, 2-5 nm in height, and 20-50 nm in length, observed by atomic force microscope. Varied morphologies were also observed when varying the pH, solvents, evaporating rate, concentration, and substrate surface. Unlike the common surfactants of single head-to-tail structure and the naturally occurring phospholipids of one head and two tails, the synthesized POP derivative is a symmetrical structure of four hydrophilic heads and one long hydrophobic block. Through the complementary noncovalent bonding forces, the molecules tend to align into molecular bundles or loops as the primary structure. The formation of different morphologies is controlled by the intermolecular forces including hydrogen bonding, aromatic pi-pi stacking, ionic charge, and hydrophobic interaction, in a concerted manner.

15.
Di Yi Jun Yi Da Xue Xue Bao ; 25(11): 1369-74, 2005 Nov.
Artigo em Zh | MEDLINE | ID: mdl-16305958

RESUMO

OBJECTIVE: To construct a new tissue-engineered bone with poly (D, L-lactide-co-glycolide) (PLGA), bone morphogenetic protein (BMP) and bone marrow-derived stem cells (BMSCs) and observe its effect in repairing segmental bone defects. METHODS: A 15-mm bone defect in the right radius was induced in New Zealand white rabbits, and the models were randomized into three groups to receive implantation of the tissue-engineered bone grafts constructed with PLGA carrying 5 mg BMP and about 1 x 10(6) BMSCs (experimental group), grafts of PLGA with about 1 x 10(6) BMSCs (control group), or grafts of exclusive PLGA (blank control group), respectively. The osteogenesis in the bone defect after the implantation on was evaluated X-ray films, and the histological changes of the tissues sampled from the bone defect 4, 8, and 12 weeks after operation were observed and new bone formation was measured by image analysis. RESULTS: The bone defect was completely repaired in the experimental group 12 weeks after the implantation, showing the best results among the 3 groups. The bone defects in the blank control group was filled with only fibrous and connective tissues at 12 weeks. CONCLUSION: This tissue-engineered bone constructed with PLGA, BMP and BMSCs possesses good ability in repairing segmental bone defect.


Assuntos
Proteínas Morfogenéticas Ósseas , Ácido Láctico/uso terapêutico , Células-Tronco Mesenquimais/citologia , Ácido Poliglicólico/uso terapêutico , Polímeros/uso terapêutico , Fraturas do Rádio/cirurgia , Engenharia Tecidual , Animais , Células da Medula Óssea/citologia , Proteínas Morfogenéticas Ósseas/genética , Proteínas Morfogenéticas Ósseas/uso terapêutico , Regeneração Óssea/efeitos dos fármacos , Substitutos Ósseos , Células Cultivadas , Feminino , Implantes Experimentais , Masculino , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Coelhos , Distribuição Aleatória
16.
Di Yi Jun Yi Da Xue Xue Bao ; 25(1): 44-7, 2005 Jan.
Artigo em Zh | MEDLINE | ID: mdl-15683996

RESUMO

OBJECTIVE: To study the in vitro biocompatibility of novel hydroxyapatite (HA) and AO artificial bone beta-tricalcium phosphate (beta-TCP) with rhesus bone marrow stromal cells (rBMSCs) . METHODS: The third passage of rBMSCs were cultured with HA and beta-TCP respectively, with the cells cultured without the materials as the control. The morphology and proliferation of cells were observed by inverted phase-contrast microscope and scanning electron microscope (SEM). MTT assay was used to semiquantitatively evaluate the cell proliferation. RESULTS: The rBMSC cocultured with HA exhibited good growth as observed under inverted phase-contrast microscope, without significant difference from the cells in the control group. Some small particles were seen pealing off from beta-TCP, and some of the cells died. Under SEM, rBMSCs showed good adhesion to HA with obvious proliferation, but the ratio of adhesive cells was not as high as that in beta-TCP group. MTT assay showed no significant difference in the cell number between HA and the control groups, but the cell number in beta-TCP group was notably less than that of control group. CONCLUSION: Novel HA has good biocompatibility with rBMSCs for bone tissue engineering, and AO artificial bone still needs improvement to serve as scaffold material for BMSCs.


Assuntos
Materiais Biocompatíveis/farmacologia , Células da Medula Óssea/citologia , Fosfatos de Cálcio/farmacologia , Hidroxiapatitas/farmacologia , Células-Tronco Mesenquimais/citologia , Implantes Absorvíveis , Animais , Substitutos Ósseos , Células Cultivadas , Macaca mulatta , Masculino
17.
Biomed Opt Express ; 6(8): 3066-73, 2015 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-26309767

RESUMO

Insulin-gold nanoclusters exhibit outstanding biocompatibility, photostability, and fluorescence quantum efficiency. However, they have never been used in superresolution microscopy, which requires nonlinear switching or saturation of fluorescence. Here we examine the fluorescence and stimulated emission depletion properties of gold nanoclusters. Their bleaching rate is very slow, demonstrating superior photostability. Surprisingly, however, the best depletion efficiency is less than 70%, whereas the depletion intensity requirement is much higher than the expectation from a simple two-level model. Fluorescence lifetime measurement revealed two distinct lifetime components, which indicate intersystem and reverse intersystem crossing during excitation. Based on population dynamic calculation, excellent agreement of the maximal depletion efficiency is found. Our work not only features the first examination of STED with metallic clusters, but also reveals the significance of molecular transition dynamics when considering a STED labeling.

18.
Di Yi Jun Yi Da Xue Xue Bao ; 23(10): 1021-4, 2003 Oct.
Artigo em Zh | MEDLINE | ID: mdl-14559682

RESUMO

OBJECTIVE: To evaluate the effect of bone morphogenetic protein (BMP) on the biological behavior of bone marrow stem cells (BMSCs) of rabbits. METHODS: BMP was either enwrapped or not in the microspheres made of chitosan and sodium alginate, and the biocompatibilities of the composites were examined by means of cell culture. The BMSCs were cultured with the two kinds of microspheres respectively, and the cell extension rate, proliferation, alkaline phosphatase activity and Coomassie blue staining of the cells were assayed. RESULTS: Inhibition of BMSC proliferation did not occur in response to in vitro culture with the microspheres, but alkaline phosphatase activity and D(lambda) values of Coomassie blue staining increased significantly in the cells cultured with BMP microspheres. CONCLUSION: BMP can increase the osteogenic capacity of BMSCs in vitro with the microspheres made of chitosan and sodium alginate as the carrier.


Assuntos
Células da Medula Óssea/efeitos dos fármacos , Proteínas Morfogenéticas Ósseas/farmacologia , Células-Tronco/efeitos dos fármacos , Engenharia Tecidual , Animais , Células da Medula Óssea/citologia , Divisão Celular , Feminino , Masculino , Microesferas , Coelhos , Células-Tronco/citologia
19.
Zhongguo Yi Xue Ke Xue Yuan Xue Bao ; 25(1): 22-5, 2003 Feb.
Artigo em Zh | MEDLINE | ID: mdl-12905601

RESUMO

OBJECTIVE: To detect the proliferation and differentiation of rabbit bone marrow mesenchymal stem cells (BMSc) transferred by retroviral vector carrying human bone morphogenetic protein 7 (hBMP-7) gene. METHODS: hBMP-7-expressing replication-deficient retroviral vector(PT-PLNCX2-hBMP7) was reconstructed using clone technique and recombinant DNA technique. BMSc were infected with the virus granules. The protein of BMP-7 gene in transferred cells were determined by immunohistochemistry. The proliferativity of the transferred cell were assayed by methabenzthiazuron (MTT) method and flow cytometer. Alkaline phosphatase (ALP) were also detected using enzyme kinetics. RESULTS: Cells transferred by PT-PLNCX2-hBMP7 expressed abundant hBMP7 protein in the cytoplasm. Positive findings were not found in those cells that were not transferred. After infected with virus there were not significant difference of cell proliferation and cell cycle between the cells transferred by hBMP-7 or not (P > 0.05). ALP activity in transferred cells were increased significantly (P < 0.01). CONCLUSIONS: hBMP-7 can be transferred and stably expressed in the cultured rabbit bone marrow stem cells. Proliferation and cell cycle of the transferred cell were not affected. hBMP7 gene transfer can be used to induce differentiation of BMSc into osteoblast-like cells.


Assuntos
Proteínas Morfogenéticas Ósseas/genética , Osteoblastos/citologia , Células-Tronco/citologia , Fator de Crescimento Transformador beta/genética , Fosfatase Alcalina/biossíntese , Animais , Células da Medula Óssea/citologia , Células da Medula Óssea/enzimologia , Proteína Morfogenética Óssea 7 , Divisão Celular , Células Cultivadas , Técnicas de Transferência de Genes , Humanos , Osteogênese , Coelhos , Células-Tronco/enzimologia , Engenharia Tecidual
20.
Zhongguo Yi Xue Ke Xue Yuan Xue Bao ; 25(1): 26-31, 2003 Feb.
Artigo em Zh | MEDLINE | ID: mdl-12905602

RESUMO

OBJECTIVE: To study whether tissue engineered bone can repair the large segment bone defect of large animal or not. To observe what character the fascia flap played during the osteanagenesis and revascularization process of tissue engineered bone. METHODS: 9 Chinese goats were made 2 cm left tibia diaphyseal defect. The repairing effect of the defects was evaluated by ECT, X-ray and histology. 27 goats were divided into three groups: group of CHAP, the defect was filled with coral hydroxyapatite (CHAP); group of tissue engineered bone, the defect was filled with CHAP + bone marrow stroma cells (BMSc); group of fascia flap, the defect was filled with CHAP + BMSc + fascia flap. After finished culturing and inducing the BMSc, CHAP of group of tissue engineered bone and of fascia flap was combined with it. Making fascia flap, different materials as described above were then implanted separately into the defects. Radionuclide bone imaging was used to monitor the revascularization of the implants at 2, 4, 8 weeks after operation. X-ray examination, optical density index of X-ray film, V-G staining of tissue slice of the implants were used at 4, 8, 12 weeks after operation, and the biomechanical character of the specimens were tested at 12 weeks post operation. RESULTS: In the first study, the defect showed no bone regeneration phenomenon. 2 cm tibia defect was an ideal animal model. In the second study, group of CHAP manifested a little trace of bone regeneration, as to group of tissue engineered bone, the defect was almost repaired totally. In group of fascia flap, with the assistance of fascia flap which gave more chance to making implants to get more nutrient, the repair was quite complete. CONCLUSIONS: The model of 2 cm caprine tibia diaphyseal defect cannot be repaired by goat itself and can satisfy the tissue engineering's demands. Tissue engineered bone had good ability to repair large segment tibia defect of goat. Fascia flap can accelerate the revascularization process of tissue engineered bone. And by this way, it augment the ability of tissue engineered bone to repair the large bone defect of goat.


Assuntos
Substitutos Ósseos , Osteogênese , Tíbia/irrigação sanguínea , Engenharia Tecidual , Animais , Células da Medula Óssea/citologia , Transplante de Medula Óssea , Regeneração Óssea/fisiologia , Células Cultivadas , Durapatita , Fáscia/transplante , Cabras , Implantes Experimentais , Neovascularização Fisiológica , Distribuição Aleatória , Células Estromais/citologia , Tíbia/lesões , Tíbia/cirurgia , Fraturas da Tíbia/cirurgia
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