Structure-activity relationship of coptis alkaloid bitterness inhibited by mPEG-PLLA / 中国中药杂志

Inhibition of bitterness is a significant measure to improve the compliance and clinical efficacy of traditional Chinese medicine(TCM) decoction. According to the characteristics of TCM decoction, such as high dispersion of bitterness components, multi-component bitterness superposition and strong instantaneous stimulation, the research group put forward a new strategy to inhibit bitterness in the early stage based on the self-assembly characteristics of amphiphilic substances in aqueous solution, in order to reduce the distribution of bitterness components in real solution and achieve the purpose of bitter-masking. It was found that the bitter-masking effect of amphiphilic substances was different on the bitter compounds of various structures. Therefore, it was speculated that there might be a certain relationship between the bitter inhibition effect and the substrate structure. In this paper, the interaction between mPEG-PLLA and five bitter alkaloids(bamatine, jatrorrhizine, berberine, epiberberine and coptisine) in Coptidis Rhizoma was studied to explore the effect of substrate structure on the inhibition of bitterness. The sensory test of volunteers was used to determine the bitter-masking effect of mPEG-PLLA on the decoction of Coptidis Rhizoma and its main bitter alkaloids. The molecular docking and molecular force field were applied to locate the bitter groups and the bitter-masking parts. The relationship between the bitter strength and the structure was analyzed by the surface electrostatic potential of the bitter alkaloids, and the correlation between the bitter-masking effect and the structural parameters of the bitter components was explored by factor analysis, so as to clarify the structure-activity relationship of mPEG-PLLA in masking the bitterness of coptis alkaloids. It was found that mPEG-PLLA had significant taste masking effect on the decoction of Coptidis Rhizoma and five alkaloids. The masking effect was obviously related to the structure of different alkaloids: the effect increased with the increase of the number of hydrogen donors, rotatable bonds, molecular weight, and hydrophobicity, and decreased with the increase of surface electrostatic potential, electrophilicity and binding energy with bitter receptors. In this study, the influence of alkaloid structure of Coptidis Rhizoma on the butter-masking effect of mPEG-PLLA was preliminarily elucidated, providing a scientific basis for better exerting the bitter-masking effect of amphiphilic block copolymers.

Biocompósitos eletrofiados de PLLA com alto conteúdo de partículas de fosfatos de cálcio funcionalizados para regeneração óssea / Electrospun PLLA biocomposites with high content of calcium phosphates functionalized for bone regeneration

Este trabalho visou a produção de suportes para crescimento celular constituídos de compósitos de poli(L-lactídeo) (PLLA) e diversos tipos de fosfatos de cálcio (CaP). A hidroxiapatita deficiente em cálcio (HAD) e o fosfato octacálcico (OCP) em tamanhos submicrométricos foram sintetizados. Hidroxiapatita (HA) e o ß-fosfato tricálcico (ß-TCP) foram adquiridos da Sigma-Aldrich. Uma mistura de HAD:ß-TCP (7:3) também foi preparada. Para melhorar a dispersão da fase mineral em uma matriz polimérica de PLLA, utilizou-se cloreto de lauroíla para funcionalizar a superfície dos CaP. Os espectros de infravermelho e a análise termogravimétrica confirmaram a presença de laurato na superfície de partículas de CaP. As partículas de HA pura também foram funcionalizadas com cloreto de lauroíla para fins comparativos. Compósitos de PLLA/CaP-laurato foram fabricados utilizando a técnica de eletrofiação. A funcionalização da superfície do CaP com laurato resultou em uma melhoria significativa na dispersão de partículas de CaP na matriz polimérica, permitindo a inclusão de até 40% da fase mineral sem comprometer as propriedades mecânicas. Microscopia eletrônica de varredura (SEM) e microscopia eletrônica de transmissão (TEM) foram utilizadas para investigar a morfologia da fibra. A perda de massa e a liberação de cálcio dos suportes durante a degradação em uma solução salina tamponada com fosfato (PBS) foram medidas. HAD e OCP se mostraram ser mais solúveis do que HA e HAD:ß-TCP (7:3). A bioatividade dos compósitos foi investigada por imersão das fibras em um fluido corporal simulado (SBF) a 37 °C e pH 7.4. Embora todos os suportes de PLLA/CaP-laurato foram capazes de formar uma camada de apatita em sua superfície após a exposição em SBF, os resultados demonstraram um aumento significativo na mineralização quando HAD, OCP e HAD:ß-TCP (7:3) são a fase mineral no compósito em vez da HA. Além disso, malhas produzidas a partir das fibras eletrofiadas de PLLA/CaP-laurato, utilizadas como suporte para crescimento celular, favoreceram a adesão e proliferação de células de fibroblastos de camundongo (NIH-3T3) e células tronco mesenquimais de dentes decíduos humanos (SHED). Finalmente, suportes a partir das malhas PLLA/HAD-laurato e PLLA/OCP-laurato apresentaram melhor desempenho para acelerar a calcificação in vitro como resultado da osteoindução de células SHED e de células pré-osteoblásticas derivadas de calvária de rato (MC3T3-E1) se comparados aqueles contendo HA e HAD:ß-TCP (7:3). Esses novos materiais são propostos como biocompósitos de rápida degradação de CaP, para serem utilizados em aplicações de regeneração óssea em ortodontia e ortopedia

This work aimed at the generation of scaffolds for cellular growth constituted by poly(L-lactide) (PLLA) and several types of calcium phosphate (CaP). Calcium deficient hydroxyapatite (HAD) and octacalcium phosphate (OCP) were synthesized in submicrometer sizes. Hydroxyapatite (HA) and ß-tricalcium phosphate (ß-TCP) were purchased from Sigma-Aldrich. A mixture of HAD:ß-TCP (7:3) also was prepared. In order to improve the dispersion of the mineral phase in a PLLA polymeric matrix, lauroyl chloride was used to functionalize the surface of CaP. Infrared spectra and thermal gravimetric analysis confirmed the presence of laurate on the surface of CaP particles. Neat HA particles were also functionalized with lauryl chloride for comparative purposes. Composites of PLLA/CaP-laurate were fabricated by electrospinning method. The functionalization of CaP surfaces resulted in significant improvement of the dispersion of CaP particles into the polymeric matrix, allowing inclusion of up to 40% of mineral phase without compromising its mechanical properties. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to investigate the morphology of the fibers. The mass loss and calcium release of the scaffolds during degradation in phosphate buffered saline (PBS) were measured. HAD and OCP are more soluble than HA and HAD:ß-TCP (7:3). The bioactivity of the composites was investigated by immersing the fibers in a simulated body fluid (SBF) at 37°C and pH 7.4. Although all PLLA/CaP-laurate can form apatite precipitation on their surface after exposition to SBF, the results demonstrate a significant enhancement in the mineralization when HAD, OCP and HAD:ß-TCP (7:3) are the mineral phase in the composite instead of HA. Furthermore, mats obtained from PLLA/CaP-laurate electrospun fibers favored the mouse fibroblast cells (NIH-3T3) and stem cells from human exfoliated deciduous teeth (SHED) attachment and proliferation. Finally, PLLA/HAD-laurate and PLLA/OCP-laurate meshes showed better performance in accelerate the calcium phosphate mineralization on its surface as a result of the in vitro osteoinduction of SHEDs and calvaria derived mouse preosteoblastic cells (MC3T3-E1) if compared of those containing HA and HAD:ß-TCP (7:3). These new materials are proposed as fast degradation CaP biocomposites to be used in bone regeneration applications in orthodontics and orthopedics

Organic-Polymeric Radial Flow Biorreactor for Liver Models / Biorreactor de flujo radial orgánico-polimérico para modelos de hígado

Abstract An artificial liver support system is based on the functional hepatocytes being cultured inside a bioreactor; this technique has being used as an effective therapy for treating chronic liver diseases in recent times. This work evaluates different parameters such as cell viability and metabolic function of the hepatocytes when cultured on a hybrid scaffold. The scaffold was built using a polypyrrole plasma coated polymer layer seeded with endothelial matrix for efficient three-dimensional hepatocyte growth within a radial flow bioreactor. The flow rate inside the bioreactor was 7 ml / min. The parts for the bioreactor where either built using food-grade steel and/or glass or the scaffolds comprise a Poly (L-lactic acid)-coated polypyrrole iodine layer or not for HepG2 culture. The results show that the Poly (L-lactic acid)-coated scaffolds increased cell proliferation by 30%, protein production by 16% and albumin secretion by 40% compared with the non-coated scaffold. All experiments were performed thrice and data was analysed by ANOVA and Tukey statistic models with a p<0.05. The obtained results demonstrated that radial flow bioreactors in conjunction with hybrid scaffolds improve hepatocytes' physiological and functional properties and could be used as an alternative therapy for patients with liver diseases.

Resumen Un sistema de soporte hepático artificial se basa en utilizar hepatocitos funcionales cultivados en un biorreactor; esta técnica ha demostrado que se puede utilizar como una terapia eficaz para el tratamiento de enfermedades crónicas del hígado en los últimos tiempos. Este trabajo evalúa diferentes parámetros tales como la viabilidad celular y la función metabólica de los hepatocitos cuando se cultivan en un andamio híbrido. El andamio fue construido usando una capa de polímero recubierto de polipirrol plasma, se sembró con un cultivo tridimensional de células endoteliales y de hepatocitos dentro de un biorreactor de flujo radial. La velocidad de flujo en el interior del biorreactor fue de 7 ml / min. Las piezas para el biorreactor fueron construidas con acero de calidad alimentaria y / o vidrio. Los andamios control fueron de ácido L-poliláctico y a estos se les agrego un revestimiento de polipirrol-yodo para el cultivo de HepG2. Los resultados muestran que el ácido L-poliláctico recubierto, aumento la proliferación celular en un 30%, la producción de proteínas en un 16% y la secreción de albúmina por 40% en comparación con el andamio no recubierto. Todos los experimentos se llevaron a cabo tres veces y los datos se analizaron mediante modelos estadísticos ANOVA y Tukey con una p <0.05. Los resultados obtenidos demostraron que los biorreactores de flujo radial conjuntamente con andamios híbridos mejoran las propiedades fisiológicas y funcionales hepatocitos y podrían utilizarse como una terapia alternativa para los pacientes con enfermedades hepáticas crónicas.

Incidence of infections associated with use of bioabsorbable implants in orthopedic surgeries

Background: The incidence of placement of osteosynthetic materials has grown worldwide. Bioabsorbable materials are more commonly used now days in Orthopedic surgeries. Implants modify the risk of infection by bacterial adhesion, tissue integration, and immunomodulation. Bacterial adhesion to implant leads to interaction between bacteria and implant. Aim: To evaluate the incidence of infections associated with use of bioabsorbable implants in Orthopedic surgeries. Materials and methods: The infection rates among 1057 patients were treated with bioabsorbable osteosynthesis devices was investigated. The implant material used was PGA in approximately three fourths of the patients. Results: Depending on the bioabsorbable material used, the infection rates varied from 0.7% (SRPLLA) to 6.5% (SR-PGA and SR-PLLA together). In a comparison with metallic osteosynthesis devices, a total 522 ankle fracture patients were studied. There was no significant difference between the infection rates of the bioabsorbable fixation group (3.2%) and metallic fixation group (4.1%). The effect of bioabsorbable implants volume on wound infections showing a significant positive correlation between the incidence of infection and the implant volume when non-stained SR-PGA or SR-PLLA implants were used. In fracture patients the raising of the implant-bone volume ratio correlated with the rising incidence of infection. Conclusion: Increasing the implant volume causes a higher incidence of wound infection when modern, non-stained implants are used. The increase in the incidence of infection is most prominent when SR-PLLA implants are used. Increasing the implant-bone volume ratio causes a higher incidence of wound infection on the tibial side.

Evaluation of electrospun PLLA-ECM scaffolds as biomaterials for bone regeneration / Avaliação de suportes eletrofiados de PLLA-ECM para regeneração óssea

The extracellular matrix (ECM) is secreted by the host tissue and is an important key for mechanisms of cell responses. The main properties of the ECM materials include biodegradability, biocompatibility, and nanostructured in a 3D fibre network. In addition, ECM is composed of important molecules like growth factors, glycosaminoglycans (GAGs), collagens, fibronectin, and lamin, while final composition depends on the native tissue. We have selected for this study ECMs from cortical bone (B-ECM) and pericardium (P-ECM) tissue. These ECMs were digested by collagenase, pepsin and trypsin. Each of these digested ECMs was used to produce PLLA-ECM based electrospun scaffolds by two different methodologies (1) non-crosslinked (NCLK) hybrid electrospun scaffolds composed of PLLA and digested ECMs and (2) PLLA-collagen electrospun scaffolds crosslinked with digested ECMs (CLK scaffolds). This research proposes the characterization of the digestion promoted by collagenase, pepsin and trypsin on the ECMs, followed by the evaluation of the potential of the digested ECMs and of the PLLA-ECM scaffolds for bone regeneration. The proteinaceous mixture, produced from the ECM digestion, had compositions, which were dependent on the type of ECM, and on the enzymatic treatment, as shown by protein quantification, GAGs quantification, TGA, SDS-page and TPEF-SHG. All the results point to an extensive digestion caused by collagenase and pepsin and a milder digestion caused by trypsin. The digested ECMs were incorporated into nanofibrous scaffolds, and the products were characterized by SEM, TGA, DSC and TPEF-SHG. The porous nanofibrous mesh from non-crosslinked scaffolds exhibited fibres without beads and a uniform diameter. However, the crosslinked scaffolds presented non-organized agglomerates around the fibres making a less porous surface. TGA and DSC suggest the incorporation of the ECMs on the scaffolds. However, the distribution of the protein on the polymer was mostly dependent on the incorporation method, as showed by TPEF-SHG. To access the biomaterial ability for bone regeneration, bone marrow mesenchymal stem cells (BMMSCs) were cultured on the scaffolds over 21 days. Osteogenic markers such as ALP activity, mineral nodule formation by ARS staining, col1a2 immunostaining, and gene expression were analysed to access how the materials could induce BMMSCs osteodifferentiation. Comparing NCLK to CLK scaffolds the key factor for osteogenesis is the release of soluble factors, showing NCLK scaffolds with a higher ability to induce mineralization than CLK scaffolds. However, when comparing the effect of the enzymatic digestion on the mineralization of the scaffolds over the days, it is possible to establish that the effect of the enzymatic treatment is also related to the type of ECM. Despite all those differences, some PLLA-ECM scaffolds exhibited potential to induce earlier mineralization, observed by the analysis of bglap, runX2, Osx, sparc and col1a2 genes as osteogenic markers

A matriz extracelular (ECM) é secretada pela células no tecido nativo e reúne propriedades chave para respostas celulares. Entre suas principais propriedades destacam-se: biodegradabilidade, biocompatibilidade e nanoestruturada tridimensionalmente. Além disso, é rica em sinalizadores celulares tais como: fatores de crescimento, glicosaminaglicanas (GAGs), colágeno, fibronectina e laminina, no entanto sua composição depende do tecido na qual se encontra. Para este estudo, foram selecionadas ECMs provenientes de osso cortical e de pericárdio. Estas ECMs foram digeridas por colagenase, pepsina e tripsina. Cada um dos produtos de digestão foi utlizado para a produção de suportes eletrofiados de PLLA-ECM, utilizando-se dois diferentes métodos de incorporação, (1) Suportes eletrofiados híbridos de PLLA-ECM obtidos a partir da eletrofiação da co-solução em 1,1,1,3,3,3-hexafluor-2-propanol, e (2) imobilização das ECM digeridas sobre suportes eletrofiados de PLLA-colágeno. O presente trabalho propõe-se a caracterizar as ECMs digeridas e a avaliar o potencial dos suportes eletrofiados de PLLA-ECM para a regeneração óssea. A mistura proteinácea obtida a partir da digestão das ECMs, mostrou que a sua composição é dependentes do tipo de ECM e da digestão enzimática, resultado este confirmado através da quantificação de proteínas, quantificação de glicosaminoglicanas, TGA, SDS-page e TPEF-SHG. A partir destes, foi observada que a colagenase é a enzima que promove a maior degradação das ECMs, enquanto que a tripsina promove uma degradação em menor escala. As matrizes digeridas foram incorporadas no material nanoestruturado, estes foram caraterizados por SEM, TGA, DSC e TPEF-SHG. Observou-se que a malha eletrofiada a partir da co-solução de PLLA-ECM exibiu a formação de fibras de diâmetro uniforme, enquanto que os suportes imobilizados apresentaram a formação de aglomerados sólidos ao redor das fibras, originando uma malha menos porosa. As análises de TGA e DSC confirmaram a incoporação das ECMs nas malhas eletrofiadas, e através da técnica de TPEF-SHG observou-se a distribuição das proteinas no polímero. O potencial dos materiais para a regeneração óssea foi avaliado através da cultura de células tronco mesenquimais de medula óssea sobre os suportes eletrofiados durante 21 dias, e em seguida, medidas de ALP, quantificação de coloração com vermelho de alizarina, imunofluorescência com anticorpo col1a2, e expressão de gênica foram analisadas para a avaliação de como os materiais eletrofiados de PLLA-ECM induzem a osteodiferenciação. Comparando-se materiais produzidos por co-solução e os materiais imobilizados foi possível observar que a resposta osteogênica é maior nos materiais híbridos devido a liberação de fatores solúveis dos suportes eletrofiados. No entanto, comparando-se o efeito da digestão enzimática na capacidade de mineralização dos suportes , é possível observar que o efeito da digestão enzimática é dependente do tipo de ECM. Em geral, foi possível observar que os suportes eletrofiados de PLLA-ECM exibem potencial para uso em engenharia de tecidos, em específico, regeneração óssea, uma vez que apresentaram-se regulados o conjunto de genes bglap, RunX2, Osx, sparc e col1a2

Characterization of progesterone loaded biodegradable blend polymeric nanoparticles / Caracterização de nanopartículas blenda poliméricas biodegradáveis contendo progesterona

ABSTRACT:The encapsulation of progesterone in poly (hydroxybutirate-co-hydroxyvalerate) (PHBV), poly (ε-caprolactone) (PCL), poly (L-lactic acid) (PLLA) nanoparticles and PHBV/PCL and PHBV/PLLA blend nanoparticles was investigated in this research. Nanoparticles were produced by miniemulsion/solvent evaporation technique with lecithin as surfactant and were characterized regarding to z-average diameter (Dz) and polydispersity (PDI), progesterone recovery yield and encapsulation efficiency. Possible interactions between progesterone and the polymer matrices were investigated by Fourier Transform Infrared Spectroscopy (FTIR). High recoveries (up to 102.43±1.80% for the PHBV/PLLA blend) and encapsulation efficiencies (up to 99.53±0.04% for PCL) were achieved and the nanoparticles presented narrow size distribution (0.12±0.03 for PLLA). PCL nanoparticles (217.5±2.12nm) presented significant difference with the Dz from all the other formulations (P<0.05). The most evident interaction between progesterone and the nanoparticles polymeric matrix was found to PHBV/PCL due to the increase in the intensity of the band located in 1631 cm-1.

RESUMO:A encapsulação de progesterona em nanopartículas de poli(hidroxibutirato-co-hidroxivalerato) (PHBV), poli (ε-caprolactona) (PCL), poli (L-ácido lático) (PLLA) e em nanopartículas blenda de PHBV/PCL e PHBV/PLLA foi investigada neste trabalho. As nanopartículas foram produzidas pela técnica de miniemulsificação/evaporação do solvente com lecitina como surfactante e foram caracterizadas em relação ao diâmetro médio em intensidade (Dz) e o índice de polidispersão (PDI), rendimento de recuperação e eficiência de encapsulação de progesterona. Possíveis interações entre progesterona e as matrizes poliméricas foram investigadas por Espectroscopia de Infravermelho por Transformada de Fourier (FTIR). Valores elevados de rendimento de recuperação (de até 102,43±1,80% para a blenda PHBV/PLLA) e eficiência de encapsulação (de até 99,53±0,04% para PCL) foram obtidos e as nanopartículas apresentaram distribuição de tamanho estreita (0,12±0,03 para PLLA). As nanopartículas de PCL (217,5±2,12nm) apresentaram diferença significativa com todas as outras formulações (P<0,05) quanto ao Dz. A interação mais evidente entre progesterona e a matriz polimérica das nanopartículas foi para a blenda PHBV / PCL, devido ao aumento na intensidade da banda localizada em 1631 cm-1.

The effects of electrospun nanofibers loading icariin on osteoblast MC3T3-E1 cells / 实用口腔医学杂志

Objective:To prepare poly-L-lactic acid(PLLA)electrospun nanofibers carrying icariin(ICA)(ICA /PLLA)and to evaluate the effects of the ICA /PLLA on MC3T3-E1 cells.Methods:ICA solution was dispersed into PLLA solution,and electrospun fibers were fabricated by W/O emulsion method.The morphology of ICA /PLLA was observed by SEM.The in vitro release kinetics of ICA /PLLA was examined.The attachment of MC3T3-E1 cells on ICA /PLLA was examined by propidiumiodide(PI)labling and ob-served under fluorescent microscope.The proliferation of the cells was measured by MTT assay.The differentiation of the cells was ob-served by alkaline phosphatase (ALP)assay.Results:In vitro,ICA was effectively released from ICA /PLLA for 22 days,cells were attached well on the surface in all groups,ICA did not affect the proliferation of MC3T3-E1 cells(P >0.05),but increased the ALP activity(P <0.05)of the cells.Conclusion:ICA /PLLA can effectively control the release of ICA and promote the differentiation of MC3T3-E1 cells.

Effect of beta-tricalcium phosphate/poly-l-lactide composites on radial bone defects of rabbit

OBJECTIVE@#To explore the effect ofβ-TCP/PLLA scaffold in repairing rabbit radial bone defects.@*METHODS@#Thirty New Zealand rabbits were divided into β-TCP /PLLA group (group A), pure PLLA group (group B) and contrast group (group C) randomly. The rabbits were sacrificed respectively after 4, 8, 12, 24 weeks and the X-ray film was performed at the same time to evaluate the repair effect in different groups.@*RESULTS@#X-ray film showed there was uneven low density bone callus development in defect region after 4 weeks in group A. The defect region was filled with neonate osseous tissue completely during 12-24 weeks. X-ray score revealed that repair of bone defect results significantly better than group B and group C.@*CONCLUSIONS@#The β-TCP /PLLA composite is capable of repairing radial bone bone defects. β-TCP/PLLA scaffold is significant because of rapid degradation ability, good histocompatibility and osteogenic action.

Experimental study of 32P-CP-PLLA microparticle on human pancreatic carcinoma in nude mice / 中华放射医学与防护杂志

Objective To study the therapeutic and toxic effects of 32 P-chromic phosphate-poly (L-lactic) acid (32p-CP-PLLA) microparticle intratumoral administration into BALB/c nude mice bearing BxPc-3 human pancreatic carcinoma.Methods Twenty four nude mice bearing tumors were injected with 0,9.3,18.5 and 37.0 M Bq 32p-CP-PLLA microparticle,respectively.The relative tumor growth rates were observed every day,and white blood cells,platelets and body weight were measured.At 14 d after administration,the tumors were removed,histological examination and immunohistochemical analysis were performed.Results The relative tumor growth rates of each treatment group was lower than 40％.Histological examination showed the degenerative necrosis at the site nearby the mircoparticle.Immunohistochemical analysis showed that the Microvessel density (MVD) and the expression of Bcl-2 in treated group were lower than those in control group.In contrast,the expression of bax in treated group were higher than those in control group.The ratio of Bcl-2/Bax protein significantly decreased in the treatment group,which were 3.83 ± 0.43,0.47 ± 0.13,1.10 ± 0.32,2.19 ± 0.57 for 0,9.3,18.5 and 37.0 MBq 32 P-CP-PLLA microparticle,respectively ( t =2.36 - 2.77,P ＜ 0.05).MVD were 31.2 ± 2.3,23.8 ± 1.5,14.8 ±0.8,11.0 ± 1.2,respectively.Dose dependence was observed in both HE and IHC staining after 14 d treatment ( t =2.30 - 2.57,P ＜ 0.05 ).Conclusions Intratumoral injection of 32p-CP-PLLA microparticle might be a safe,easy and effective radionuclide interventional therapy for pancreatic carcinoma.

Preenchimentos faciais - parte um / Dermal fillers - part one

Nos últimos anos, presenciamos o aparecimento de grande variedade de preenchimentos dérmicos. Eles permitiram que aumentasse nossa variedade de escolha, nunca tida antes. Neste artigo abordaremos algumas novas opções de preenchedores.

The metabolism of ~(32)P-CP-PLLA seed implanted in the liver and its damage to the normal liver tissue: a study in the experimental dogs / 介入放射学杂志

Objective To investigate the effects of intratumoral implantation of ~(32)P-CP-PLLA seeds on the normal canine liver tissue and to exolore the metabolism of ~(32)P-CP-PLLA seeds implanted in the liver of experimental dogs.Methods Twelve beagles were enrolled in this study.The dogs were randomly and equally divided into four groups:group A(185 MBq),group B(370 MBq),group C(740 MBq)and group D(0 MBq).By using laparotomy procedure ~(32)P-CP-PLLA seeds were implanted into dog's liver.CT scan was performed before operation as well as before the dog was sacrificed.All dogs were sacrificed three months after the implantation.Before the procedure and 1,2,4,8 and 12 weeks after the procedure the blood tests and serum biochemical tests were conducted.One dog from group B and group C was selected respectively and was fed in a metabolic cage.Within one month after the procedure the cpm in feces and in urine was determined every 24 hours.One dog was picked out from each of the three groups and was punctured to get its liver tissue for pathologic exam each time at 1,2,4,8 and 12 weeks after the implantation,and SPECT imaging was also performed at the same time.Pathologic study,both macroscopic and microscopic(including optical and electronic microscopy)was made to observe the liver damage after the dog was sacrificed.The statistical analysis was processed by using SPSS 13.0 software and the measuring data were expressed with mean±standard deviation((x)±s).Results Two months after the procedure,serological examination found that the serum alkaline phosphatase(BKP)in both group Band group C was significantly higher than that in other groups,the difference was statistically significant (P ＜0.05),and the BKP levels returned to normal in three months.The postoperative 30-day inspection of the urine showed that the radioactive particles slowly released into the body and eliminated from the body with the urine and feces,mainly through the renal excretion.The 30-day cumulative percentage of eliminated radioactive dose in the urine and in the feces was 6.34% and 11.64% respectively.No sign of particle displacement was found on SPECT imaging.On autopsy three months after the implantation,the size of the radioactive seeds became smaller and fragile.With the radioactive dose used increasing,the area of liver damage at the site of seed implantation became bigger,which was demonstrated on CT scan,macroscopic exam and pathologic study.The local damaged focus of the liver caused by ~(32)P-CP-PLLA seeds was manifested as a spherical lesion which was encysted by a layer of fibrous tissue with an edematous zone peripherally.Conclusion The implantation of ~(32)P-CP-PLLA seeds in dog's liver causes only localized hepatic damage with no general adverse effects.The implanted seeds can slowly release the radioactive dose and will not immigrate to other organs in the body.Besides,the seeds possess excellent stability,targeted orientation and safety.

Long-term toxicity studies on 32P-chromic phosphate-poly-L lactic acid seeds interstitial delivery of beagle dogs / 中华放射医学与防护杂志

Objective To explore the toxicity and safety of 32P-CP-PLLA seeds interstitial implantation. Methods 30 beagle dogs were randomly divided into 10 groups according to different drugs (32P-CP-PLLA and 32P-CP),different doses (185, 370 and 740 MBq) and different sites (gluteus and liver). At different time-points after surgery, the weights of dogs were measured. The blood routine and blood biochemical indexes,PC Ⅲ ,HA,CG,PCⅣ and LN were examined. ECT imaging was performed and histology was observed dynamically. Blood, urine and faeces were measured continuously for 12 weeks and 30 days, respectively. Results ECT imaging demonstrated in seed groups and 32P-CP muscle groups radioactivity concentrated continuously in the area of implantation, without liver imaging. 471.67 MBq/m2 of 32 P-CP was injected in liver,while the absorbed dose was 31 Gy,without significant liver damage. When the dose was 794. 28 MBq/m2 , the absorbed dose was 56 Gy,with strong liver and systemic toxicity. But implanting seeds at the same or higher dose, the absorbed dose was 89.83-178.68 Gy in the area of implantation, and the rest liver was 1.09-2. 18 Gy,without liver damage. Dogs in liver group died at 23, 29 and 45 d, respectively, and the inspections of liver fibrosis were higher than the means of the other groups.Blood routine and blood biochemistry indexes between the other groups showed no significant differences.Effective half-life of 32P-CP-PLLA was 11.78 d, while that of 32P-CP was 6. 82 d in liver, and 8. 73 d in gluteus. Mild to moderate injury were found in liver group at 4 weeks. Moderate to serious injury were found. Liver cell necrosis and proliferation were found at 4-6 weeks in other liver groups. In muscle groups,only cellular edema was found in muscle groups at 2 week. The radioactivity count rate in blood for seed groups showed slowly jagged decreasing over time, and decreased exponentially for 32PCP groups. The radioactivity count rate in urine and faeces were multi-peak descending in seed groups. Conclusions 32P-CP-PLLA seeds have the advantages of suitable target location, degradable, non-migration and easy to protection, and it could be used in treatment for different blood supply types of solid tumors. Liver of beagle dog could endure the dose from 32 P-CP-PLLA seed twice as 32P-CP lethal dose.

Bone tissue engineering using PLLA/HA composite scaffold and bone marrow mesenchymal stem cell

Study on biocompatibility of the nano-PLLA-b-PCL with canine chondrocytes in vitro / 中国矫形外科杂志

[Objective] To evaluate the cellular biocompatibility of the nano poly(L-lactic acid)-block-poly(?-caprolactone)(Nano-PLLA-b-PCL)with canine articular cells and its feasibility as a scaffold for the cartilage tissue engineering.[Methods]Nano-PLLA-b-PCL was made by liquid-liquid phase separation.Canine articular cells were isolated and multiplied in vitro.The passage 3 cells were seeded onto the PLLA-b-PCL films and cultured in the 2-dimensional environment.The cytotoxicity was measured with MTT assay.Cellular Morphological changes were observed by phase-contrast microscopy and Hoechst33342 fluorometric method.Another passage 3 cells were seeded onto the Nano-PLLA-b-PCL scaffolds(experiment group),PLLA-b-PCL scaffolds(control group)and cultured in the 3-dimensional environment for 3 weeks.The ratio of cell adhesion was detected by cell counting method.The morphological changes of cells were observed by scanning electron microscopy.The protein content in seeded cells were determined by bioinchoninic acid assay(BCA).The content of DNA was quantified using Hoechst33258 assay.[Results]MTT assay showed the PLLA-b-PCL had no cytotoxicity.The seeded cells adhered and proliferated well into the Nano-PLLA-b-PCL scaffolds,and they maintained good cell phenotype.After 21-day cell culture within the Nano-PLLA-b-PCL scaffolds,the chondrocyte DNA and protein contents increased with time.Moreover,the content of DNA and protein was higher in the experiment group than that in the control group,respectively(P

Experimental research of repairing large segment of dogs bone defect with massive bioactive bone substitutes / 中国矫形外科杂志

[Objective]To evaluate the effect of massive bioactive bone substitute in repairing large animals bone defect and to know its degrading rate.[Method]The massive Polylevolactic acid?collage calcium phosphate(PLLA?cTCP) carrieres by rapid forming technology was making,and then compounding rhBMP-2 and carrieres in a ratio of 3mg rhBMP-2 to one carrier was compounded to prepare the massive bioactive bone substitutes for dogs bone defect.Then the massive bone substitutes were implanted into 2.0cm dogss radius defects in the experiment group,and the massive carriers were implanted into in the control group.The repairing effect was evaluated by radiography,histology and biomechanics,and the degrading rate of the substitues was calculated in an image analysis apparatus.[Result]Radiographically,in the experiment group,the defects were connected by callus in all dogs in 12 weeks postoperatively;in 24 weeks,the callus rebuilt well.But in the control group,there was no callus formed in 24 weeks postoperatively,and the defects were not repaired.Histologically,in 12 weeks postoperatively,the outer layer of the callus in the experiment groups was lamellar bone and the center were trabecular bone,myeloid tissue and partial degrading carrier;in 24 weeks,the lamellar bone was more compact,trabecular bone decreased,myeloid tissue increased,and the carrier degraded more.In the control group,in 12 weeks postoperatively,the fibrous tissue wrapped and infiltrated into carrier,at the same time,part of the carrier degraded;in 24 weeks,the carrier was divided up by fibrous tissue and degraded more.The degrading rate of the carder in 12 weeks in the experiment group was 43.2%,in the control group was 35.7%,in 24 weeks 58.4% and 45.4%.Biomechanics,in 24 weeks after postoperation,the radius strength in the experiment group was superior to that in the normal bone.[Conclusion]The massive bioactive bone substitutes have satisfactory repairing effect on the radius bone defects of the large animal,but its degrading rate needs improving.

Research progress of biodegradable stent in the application for benign luminal stenosis / 介入放射学杂志

Stent implantation plays an significant role in the interventional therapy, mainly with permanent stent, possessing many disadvantages such as restenosis and inflammatory hyperplasia and can thus hardly be used in children and nonmalignant stenosis. Biodegradable stent has theoretical capability to solve these problems and acquires a bright future. Nowadays, with the development of material industry and manufacture craft, biodegradable stent technique has turned up to be mature in last decades. Through the strict animal experiments and prophase of clinic application, satisfactory result has been acquired. We believe that bioabsorbable stent will be widely used in many benign diseases which would be a good supplement for permanent stent in the near future.

Cellular compatibility of PCL-b-PLLA scaffolds and chondrocytal compound in vitro / 医学研究生学报

0.05). The scaffolds produced no effect on the cell proliferation and had a low cytotoxicity, with chondrocytes tiled and lots of microspikes and matrixes secreted on the surface. Conclusion: The PCL-b-PLLA scaffold has a good compatibility with cells and is suitable for cartilage tissue engineering.

Culture of Chondrocytes on Scaffolds with Different Pore Network of PLGA and PLLA

This study was performed to investigate the in vitro proliferation and migration of rabbit auricular chondrocytes into the various sized pore of PLLA and PLGA scaffolds. The chondrocytes were harvested, expanded, and seeded onto PLGA(50 : 50, 75 : 25, 85 : 15) and PLLA scaffold having either small(50 - 100 micrometer) or large(300 - 350 micrometer) pores. On the 4th and 8th week after culture, histologic observation and quantitative DNA assay were done. We noted that the largest amount of DNA was found in the 85 : 15 PLGA sponges than others, and in the 4th and 8th week, some amount of DNA was detected in the lower portion of 85 : 15 PLGA sponge only, and DNA amounts were increased during the culture period in the 85 : 15 PLGA, significantly. We also found that the numbers of cells were low in middle portion of scaffolds, and in large pore-sized group of 85 : 15 PLGA, there were many cells in the lower portion of the scaffolds more than that of small pore group. In conclusion, the pore size of the scaffold for chondrocyte culture is important for cell migration and proliferation, and PLGA, especially 85 : 15 PLGA with 300- 350 micrometer sized pore is the more suitable biomatrix for proliferation and migration of the chondrocytes.

In Vivo Biodegradability of PLLA and PLGA Sponge using Non-toxic Effevescent as a Porogen Additive

In many tissue engineering application, highly open porous scaffolds are required for efficient cell seeding and culture. Synthetic biodegradable polymers such as poly (L-lactic acid)(PLLA) and its copolymers with D-lactic and glycolic acids(PLGA) are widely used as a porous scaffold. The suitable biodegradability and dimensional stability of porous scaffolds during in vivo implantation play an important role in tissue engineering application. In this study, we investigated in vivo biodegradation and dimensional stability of acellular porous polymer scaffolds prepared by using a gas foaming technique with non-toxic effervescent mixture. In addition, we have engineered cartilage tissue 3D cultured on PLGA scaffolds in nude mouse in order to compare with degradation and deformation on acellular porous polymer scaffolds and to form tissue-engineered cartilage tissue. Sodium bicarbonate and citric acid crystals were used as an effervescent mixture. These particles were milled and sieved to yield various range of sizes(50 - 100, 100 - 300, and > 300 micrometer). After polymer scaffolds fabricated, biodegradation test was performed in subcutaneous tissue of male rats during 12 weeks. Degradability of polymer scaffolds were evaluated by weight difference, gel permeation chromatography(GPC), and SEM as each period. Tissue-engineered cartilage by transplanting 3D cultured chondrocytes onto PLGA 85:15 scaffolds in nude mouse was also made and compared with acellular scaffolds. In conclusion, highly open porous biodegradable scaffolds are prepared by gas foaming method using sodium bicarbonate and citric acid as a non-toxic effervescent mixture. Furthermore, tissue-engineered cartilage formation by in vivo 3D culture onto modified PLGA scaffolds in nude mouse was significantly improved as compared to controls.

Effects of Tetracycline-loaded Poly(L-lactide) Barrier Membranes on Guided Bone Regeneration in Beagle Dog / 대한치주과학회지

Application of membranes for guided tissue regeneration(GTR) have been confined to the subgingival barrier functions; however, many studies have provided evidence that some drugs, including tetracycline, initially can promote the growth of periodontal ligament or alveolar bone in peridontal therapy. Osseous regeneration in periodontal defects is increased by local administration of tetracycline due to its anti-collagenolytic effect, which enhances bone-forming ability via osteoblast cell chemotaxis and reduced bone resorption. The aim of this study was to evaluate effects of tetracycline loaded poly-L-lactide(PLLA) barrier membranes for guided bone regenerative potential. Tetracycline was incorporated into the PLLA membrane with the ratio 10% to PLLA by weight. Ability to guided bone regeneration of the membranes were tested by measuring new bone in the tibial defects(7x10x5 mm3) of the beagle dog for 4, 5, and 6 weeks. In control, drug-unloaded PLLA membranes were used in same size of defect. In histologic finding of the defect area, a few inflammatory cells were observed in both groups. These membrane were not perforated by connective tissue and maintained their mechanical integrity for the barrier function for 4-6 weeks. New bone formation was greater in defects covered by tetracycline-loaded membrane than in defects covered by drug- unloaded membranes. In bone regeneration guiding potential test, tetracycline-loaded membrane was more effective than drug- unloaded membranes(p<0.05). These results suggest that tetracycline-loaded PLLA membranes potentially enhance guided bone regenerative efficacy and might be a useful barrier for GTR in periodontal treatment.