Effect of silibinin and trans-chalcone in an Alzheimer's disease-like model generated by insulin amyloids

Amyloid fibrils are characteristic of several disorders including Alzheimer's disease (AD), with no cure or preventive therapy. Diminishing amyloid deposits using aromatic compounds is an interesting approach toward AD treatment. The present study examined the anti-fibrillogenic effects of silibinin and trans-chalcone in vitro, in vivo, and in silico on insulin amyloids. In vitro incubation of insulin at 37°C for 24 h induced amyloid formation. Addition of trans-chalcone and silibinin to insulin led to reduced amounts of fibrils as shown by thioflavin S fluorescence and Congo red absorption spectroscopy, with a better effect observed for silibinin. In vivo bilateral injection of fibrils formed by incubation of insulin in the presence or absence of silibinin and trans-chalcone or insulin fibrils plus the compounds in rats' hippocampus was performed to obtain AD characteristics. Passive avoidance (PA) test showed that treatment with both compounds efficiently increased latency compared with the model group. Histological investigation of the hippocampus in the cornu ammonis (CA1) and dentate gyrus (DG) regions of the rat's brain stained with hematoxylin-eosin and thioflavin S showed an inhibitory effect on amyloid aggregation and markedly reduced amyloid plaques. In silico, a docking experiment on native and fibrillar forms of insulin provided an insight onto the possible binding site of the compounds. In conclusion, these small aromatic compounds are suggested to have a protective effect on AD.

Effects of small leucine-rich proteoglycans on corneal transparency / 中华实验眼科杂志

Small leucine-rich proteoglycans (SLRPs) are necessary structural ingredients of the cornea, which are vital for the establishment and maintenance of corneal transparency.SLRPs are mainly located in the corneal stroma and can be divided into class Ⅰ, class Ⅱ, and class Ⅲ.The compensatory and cooperative interactions among SLRPs regulate the formation and assembly of stromal collagen fibrils, thereby maintaining the highly ordered arrangement of collagen fibrils, and establishing corneal transparency.Decorin and lumican are the main functional components of class Ⅰ and class Ⅱ SLRPs, respectively, and changes in their expression or abnormities in the structure of their core proteins affect the natural content and arrangement of other stromal extracellular matrix components, ultimately resulting in abnormal fibril formation, assembly, and arrangement, causing corneal opacity.SLRPs can regulate corneal wound healing and stromal matrix remodeling via binding to fibrotic molecules and their receptors, which provides bases for corneal diseases therapy and study of molecular mechanisms of corneal transparency.The bioactivities and the role of SLRPs in corneal transparency were reviewed in this article.

Evaluation of self-prepared absorbable hemostatic cellulose fibrils / 浙江大学学报·医学版

To evaluate the effectiveness and safety of self-prepared absorbable hemostatic fibrils.A kind of absorbable hemostatic fibrils were prepared by self-developed patent technique. The physical form and molecular structure of the fibrils and a marketed product Surgicel were characterized by general observation and infrared spectroscopy; the carboxyl content, pH value and relative molecular mass of fibrils were determined by potentiometric titration method, pH meter and copper ethylenediamine method, respectively. The behavior of the fibrils and Surgicel in contact with blood was observed by inverted microscope, the cytotoxicity was evaluated by agarose diffusion cell assay . The external iliac artery hemorrhage model and the back muscle infiltration model in rats were established. The hemostatic effectiveness of the fibrils was investigated by hemostasis time and blood weight, and the degradation and biosafety of fibrils were investigated by observation photography, immune organ weighing, hematology and coagulation index measuring, and histopathological examination. The fibrils and Surgicel had similar molecular structures. Compared with the raw material regenerated cellulose, the typical carboxyl stretching vibration absorption peak of -COOH appeared near in both fibrils and Surgicel. The carboxyl content of the two materials was about 20%, and the pH value was about 3. The relative molecular mass of the fibers after oxidation was 4466±79, which was close to that of Surgicel(>0.05). After contacting with blood, the volume of fibrils and Surgicel expanded, and absorbed blood of dozens of times as their own weight. The results of agar diffusion test showed that the fibrils had no cytotoxicity. The results of animal experiments showed that the hemostasis completed within and there was no significant difference in blood weight and speed of hemostasis between two products (both >0.05). The fibrils could be degraded 1 week after being implanted to the bleeding sites of the muscle. There were no pathological effects on the appearance, body weight, food intake, immunological tissue thymus, spleen, lymph nodes, hematology and coagulation indexes of the rats, and no obvious abnormality found in the histopathological examination. The prepared absorbable hemostatic fibrils have excellent biological safety and effectiveness.

Formation of FADD amyloid fiber and its role in immune signaling in Drosophila melanogaster / 生物工程学报

In this research, we studied the formation of Drosophila melanogaster FADD (Fas-associated death domain-containing protein) amyloid fiber and its influence on signal transduction in IMD (Immune deficiency) signaling pathway to better understand the regulation mechanism of Drosophila innate immune signaling pathway, which will provide reference for the immune regulation in other species. First, we purified dFADD protein expressed in Escherichia coli and performed Sulfur flavin T binding and transmission electron microscopy to identify the dFADD amyloid fibers formed in vitro. Then we investigated the formation of dFADD polymers in S2 cells using SDD-AGE and confocal microscope. We also constructed dFADD mutants to find out which domain is essential to fiber formation and its effect on IMD signal transduction. Our results revealed that dFADD could be polymerized to form amyloid fiber polymers in vitro and inside the cells. Formation of fibers relies on DED (Death-effector domain) domain of dFADD, since DED domain-deleted mutant existed as a monomer. Dual luciferase reporter assay showed that intact DED domain was required for the induction of downstream antimicrobial peptides, indicating that fiber formation was the key to IMD signal transduction. Our study revealed the role of dFADD in mediating the cascade between IMD and Dredd in the IMD signaling pathway by forming amyloid fibers, suggesting an evolutionarily conserved regulatory mechanism of innate immune signaling pathway.

Prediction of fibril formation by early-stage amyloid peptide aggregation / 药物分析学报

Amyloid fibrils are found in systemic amyloidosis diseases such as Alzheimer's disease, Parkinson's disease, and type II diabetes. Currently, these diseases are diagnosed by observation of fibrils or plaques, which is an ineffective method for early diagnosis and treatment of disease. The goal of this study was to develop a simple and quick method to predict the possibility and speed of fibril formation before its occurrence. Oligomers generated from seven representative peptide segments were first isolated and detected by ion-mobility mass spectrometry (IM-MS). Then, their assemblies were disrupted using formic acid (FA). Interestingly, oligomers that showed small ion intensity changes upon FA addition had rapid fibril formation. By contrast, oligomers that had large ion intensity changes generated fibrils slowly. Two control peptides (aggregation/no fibrils and no aggregation/no fibrils) did not show changes in their ion intensities, which confirmed the ability of this method to predict amyloid formation. In summary, the developed method correlated MS intensity ratio changes of peptide oligomers on FA addition with their amyloid propensities. This method will be useful for monitoring peptide/protein aggregation behavior and essential for their mechanism studies.

Biomimetic remineralization of dentin / 口腔疾病防治

@#In recent years, due to precise control of the amorphous mineral precursor in the demineralization of dentine collagen fibers in orderly deposition, forming apatite crystals similar to the natural mineralized dentin, the bottom-up remineralization approach which does not depend on the existence of seed crystallites, dentin biomimetic mineralization techniques gradually become a hotspot in the research field of restoration of demineralized dentin caused by dental caries. This paper reviews the changing concepts and practices of the remineralization of demineralized dentin, emphasizing biomimetic remineralization studies. The results of the literature review show that the traditional dentin remineralization method is usually a disordered mixture of demineralized dentin and minerals, so mineralized dentin is not comparable to natural mineralized dentin in terms of the morphological characteristics and mechanical properties. With its gradual increase in recent years, dentine biomimetic mineralization technology perfectly resembles the minerals in the dentin overlapping sequence arranged with the dentine collagen fiber structure characteristics, leading to greatly improved microstructural, physical and chemical properties. As a result, dentine biomimetic mineralization technology is expected to achieve new breakthroughs in the fields of resin-dentin bonding mixing layers and the decay of dentin. At present, the technical obstacles that need to be overcome in the clinical application of the biomimetic remineralization of dentin are how to continuously supplement all the active ingredients needed for mineralization in the process of remineralization and how to keep the mechanical properties of the parent material unchanged while slowly releasing all ingredients. Researchers have successively proposed three-step transportation of the biomimetic remineralization of raw materials, as well as the preparation of mineralization precursors stabilized by polymers in advance and the reuse of mesoporous silicon nanomaterials for the transportation of the mineralized ingredient system. The concept described above provides the preliminary in vitro experimental basis for the transformation of the biomimetic remineralization strategy of dentin in clinical applications.

Effect of arbuscular mycorrhizal fungi on endogenous hormones in Paris polyphylla var. yunnanensis / 中草药

Objective In order to study the dynamic variation of endogenous hormones in Paris polyphylla var. yunnanensis inoculated by different foreign arbuscular mycorrhizal fungi species. Methods With sterilized soil as growth substrate, the fresh seeds of P. polyphylla var. yunnanensis were co-cultured with 28 arbuscular mycorrhizal (AM) fungi species under the condition of pot culture at room temperature. The rhizomes and fibrils of P. polyphylla var. yunnanensis were collected, and the contents of endogenous hormone zygotic nucleotides (ZR), gibberellin (GA), indole acetic acid (IAA) and abscisic acid (ABA) were determined by HPLC, then content and proportion of endogenous hormones were analyzed, respectively. Results The results showed that it could increase the mycorrhizal colonization rate and seedling rate of P. polyphylla var. yunnanensis inoculated by different foreign AM fungi species. The content change of ZR, GA, IAA and ABA appears different in the rhizomes and seedling fibrils of P. polyphylla var. yunnanensis after the inoculation of AM fungi species, but it has preferences. Compared with the control group (CK), the content of ZR and GA rose obviously in the rhizomes and seedling fibrils of P. polyphylla var. yunnanensis after the inoculation of AM fungi species, the content of ABA reduced and the content of IAA did not obvious change. The ABA/ZR proportion, ABA/GA proportion and ABA/IAA proportion reduced obviously in the rhizomes of P. polyphylla var. yunnanensis after the inoculation of AM fungi species but there was different change in seedling fibrils of P. polyphylla var. yunnanensis. Conclusion In conclusion, it is inferred that the AM fungi can promote the survival rate of the P. polyphylla var. yunnanensis seedlings, and the different AM fungi strains affect the content of endogenous hormones of P. polyphylla var. yunnanensis.

Anticoagulant therapy in patients w ith atrial fibrillation:safety and compliance / 国际脑血管病杂志

The most important harms of atrial fibrilation are stroke and the embolic events of the systemic circulation. The latest data have show n that the etiology of up to 1/3 of stroke patients w as atrial fibrilation. The stroke morbidity and mortality caused by atrial fibrilation are higher than other types of stroke. So the prevention of stroke is very important for patients with atrial fibrilation. The anticoagulant therapy is the core strategy for stroke prevention in patients with atrial fibrilation. This article reviews the advances in research on the safety and compliance of anticoagulation therapy in patients w ith atrial fibrilation.

Comparative Study on Four Polyphyllins Content in Paridis Rhizome and Fibril / 中国药师

Objective:To investigate the distribution of four polyphyllins in different parts of paris polyphylla by means of compa-ring the contents of relative constituents in paridis rhizome and fibril to provide reference for comprehensive exploitation and utilization of paris polyphylla. Methods:Paris polyphylla samples were collected from Wudang mountain area and Shennongjia forest area. The contents of main secondary metabolites including polyphillinⅠ,Ⅱ,Ⅵ andⅦin paridis rhizome and fibril were evaluated by HPLC. Results:The four polyphyllins contents had obvious differences in different parts of polyphylla. The total content of four polyphillins in fibril was significantly higher than that in rhizome. Diosgenin compositions had no significant difference in the two parts, and the con-tents of pennogenin compositions in fibril showed significantly higher than those in rhizome. Conclusion:As for the main chemical com-positions contained in polyphylla, there is chemistry equality between fibril and rhizome, thus both of them can be used for medicine. However, as for the contents of four steroidal saponins, the distribution of secondary metabolites has obvious difference between fibril and rhizome, and the result may be caused by steroidal saponins transferred to rhizome for storage after the synthesis in fibril.

Autophagy-related gene Beclin-1 expression in neuron-like differentiation of human bone marrow mesenchymal stem cells / 中国组织工程研究

BACKGROUND:Bone marrow mesenchymal stem cells have potential to self-renewal and multi-lineage differentiation. But after a long period of culture in vitro, the proliferation and differentiation capacities of bone marrow mesenchymal stem cells gradual y loss, the mechanism underlying which is not clear now. OBJECTIVE:To observe the expression of autophagy-related gene Beclin-1 in differentiation from human bone marrow mesenchymal stem cells into neuron-like cells in vitro. METHODS:The changes of morphological characteristics of neuron-like cells differentiated from human bone marrow mesenchymal stem cells induced by epidermal growth factor were observed. The expression of neuron-specific enolase and glial fibril ary acidic protein in treated and untreated human bone marrow mesenchymal stem cells were detected using immunocytochemistry. The Beclin-1 protein expressions were detected by western blot before and after induction. RESULTS AND CONCLUSION:After being induced, human bone marrow mesenchymal stem cells presented classical neuron-like morphology;the expressions of neuron-specific enolase and glial fibril ary acidic protein were 78.7%and 8.1%, respectively. The expression of Beclin-1 protein was changed correspondingly during the induction, which increased after 30 minutes of induction and decreased gradual y after 1 hour of induction. Human bone marrow mesenchymal stem cells could be induced into neuron-like cells in vitro by epidermal growth factor. Autophagy-related gene was highly expressed in the induction of early differentiation and the expression gradual y reduced until it remained at a low level during the differentiation.

Sodium aescinate reduces glial fibriallary acidic protein expression after spinal cord injury / 中国组织工程研究

BACKGROUND:The methylprednisolone pulse therapy in early period of spinal cord injury can attenuate the pathological degree of spinal cord injury, however no breakthrough was found within recent 20 years. OBJECTIVE:To observe the protection effects of sodium aescinate on the nerve cellapoptosis and expression of glial fibrial ary acidic protein (GFAP) in the early spinal cord injured rats. METHODS:Spinal cord injury models were established with the modified Al en’s method in 180 Sprague-Dawley rats, and were randomly divided into three groups, with 60 rats in each group. Immediately after injury, the rats in three groups were intraperitoneal y injected with sodium aescinate (5 mg/kg), methylprednisolone (100 mg/kg) and equal saline, respectively, once per day. At 8 hours, 24 hours, 96 hours and 7 days, 14 days after injury, rats were sacrificed and the injured segments were resected for hematoxylin-eosin staining and immunohistochemical staining, the nerve cellapoptosis and GFAP expression were detected. RESULTS AND CONCLUSION:The apoptotic nerve cells were seen at 8 hours after injury and the number of apoptotic cells reached the peak at 7 days, the edema was attenuated at 14 days without less nerve cellapoptosis in al groups, significantly fewer apoptotic nerve cells can be seen in sodium aescinate and methylprednisolone groups compared with the control group (P0.05), which was lower than methylprednisolone group (P<0.05);after 96 hours, methylprednisolone group and sodium aescinate group were both significantly lower than control group (P<0.05). Furthermore, the decreasing expression was observed in al groups after 7 days. Sodium ascinate has obvious protection effects on nerve cells in spinal cord injured rats and promotes neurological function through decreasing GFAP expression after injury. The efficacy of sodium ascinate is equal to that of methylprednisolone within 2 hours.

Reinforcement property of collagen fibril in articular cartilage / 医用生物力学

Objective To evaluate and compare the differences in COSMOL articular cartilage (AC) simulation due to the application of collagen fibril reinforcement property. Methods Collagen fiber stress was modeled independently according to its orientation in AC and written into the original poro-elastic AC model. Function call was used to avoid quadric strain term. The iteration of solver was increased for better convergence. Results The initial superficial Y displacement of the reinforced model was 15 μm, which was 17.6% of the non-reinforced model. X normal strain of the reinforced model was 10% of that in the non-reinforced model, but the superficial X normal stress of the reinforced model was 10 times higher than that of the non-reinforced model. Conclusions The application of collagen fibril reinforcement property in COMSOL AC simulation is achieved, which provided the computational model and theoretical analysis for collagen fibril lesion. Lateral reinforcement of collagen fiber can constrain the vertical strain, by which enlarge AC load capacity and improve AC mechanical properties.

Characterization of açaí (E. oleracea) fruits and its processing residues

The aim of this work was to study the source of the açaí residue for its possible commercial applications by characterizing the fruit (fresh and dry mass), and performing an anatomic study of the pericarp from which were identified the origin of the anthocyanins, and fatty acids, and fibers; also the vascular system, its fibers constituents and fibrils were characterized. It was concluded that anthocyanins were located on the epiderm and external parenchyma, and that solids retained on the sieve come from the sclerenchyma, and that the fatty acids come from the storage parenchyma. The vascular tissue was formed by the fibers around 20 mm length. The length distribution of the fibrils had a mean length of 580µm.

Analysis of Microstructure of Plant Fibers with Different Hemicellulose Content by Solid State Nuclear Magnetic Resonance and Atomic Force Microscope / 分析化学

Fibers with different hemicellulose contents were produced using various degree removal of hemicellulose to obtain large differences in cellulose and hemicellulose proportions at a similar lignin content. Solid state cross polarisation magic angle spinning carbon-13 nuclear magnetic resonance(CP/MAS ~(13)C-NMR) and atomic force microscope(AFM) had been employed to investigate the microstructure of fibers. The results showed that there was an increase in relative content of para-crystalline cellulose with the decreas of hemicellulose content obtained by the spectral fitting for the cellulose C1-region(δ 102-108). The elementary fibril size was relatively constant between 4.0 and 4.3 nm for the three samples obtained by the spectral fitting for the cellulose C4-region(δ 80-92). The difference in elementary fibril size between the samples was not significant. However, the elementary fibril aggregate size increased from 17.9 to 22.2 nm with the decreas of hemicellulose content, which was a significant change. The results of AFM analysis showed that the fiber with a high hemicellulose content had a porous surface structure. In fibres with a low hemicellulose content, the elementary fibril aggregates formed a much more compact surface structure. Lower hemicellulose content can promote the partially irreversible microfibril aggregation, which caused tensions in the microfibrils due to the finite dimensions of the cell wall, amounting to stress in the microfibrils. However, the porous structure can be improved as hemicellulose content decreased to a certain extent.

The Ultrastructural Observations of the Normal Anterior Cruciate Ligament / 中国运动医学杂志

Objective To study the ultrastructure of the anterior cruciate ligament.Methods Specimens were procured from seven patients with arthroscopy and observed under scanning and transmission electron microscope. Results Fibrils of normal anterior cruciate ligament arrayed in compact parallel form with waviness.Connecting fibers existed between fibrils.Diameters of fibrils were different with range of 30nm to 60nm mostly.Fibroblasts were distributed along with the fibrils.Active cells excrete filamentous collagen fibrils.Conclusion The ultrastructure of the anterior cruciate ligament was correlated with its function status.Mature fibroblasts existed in the ligament.

Effect of Culture Conditions on the Protein Fibril Expression of Candida albicans

Candida albicans is an important human pathogen that causes systemic infections, predominantly among population with weakened immune system. Cell wall structures of C. albicans are important to adhere to host tissue and evade to host immune system. Among cell wall structure, the outermost fibrillar layer of C. albicans is of interest since it may play important roles in antigenicity, phagocytosis, and adherence. The expression of virulent factors could be affected by the growth conditions. The dynamic nature of the cell surface alters the physical properties of the fungal interface with host cells and thereby influences adhesion to the host and recognition by components of the host immune system. In this study, we investigated the effects of culture conditions on cell surface fibril expression of C. albicans by a transmitting electron microscopy and SDS-PAGE. The protein fibril of C. albicans was expressed in the presence of whole serum, however, the fibril expression was decreased in 25% serum and serum containing 1% glucose. Also, germ tube can be induced by serum, RMPI medium, N-acetyl glucosamine, and 39 degrees C culture condition, hence, the fibrillar structure of C. albicans was detected only in serum-induced germ tube. The expression of fibril layer and the major fibril proteins of 66, 47, 30 kDa were reduced as increasing cell concentration of intial inoculum from 2x10(7) cells/ml to 8x10(7) cells/ml. The fibrillar layer of C. albicans was expressed in serum early within 10 min, and the thickness of fibril layer was increased according to the increase of culture time. When the fibrillar proteins were analysed by SDS-PAGE, major protein of 30 kDa was maintained continuously during over night culture although expression of the other proteins were various. These results suggest that expression of serum induced protein fibril is influenced by culture conditions and is not related to hyphal transition of C. albicans.

Hypertrophy of the Patellar Tendon induced by Local Injection of TGF-beta1 in Mature Rats / 대한정형외과연구학회지

PURPOSE: The effects of local injection of TGF-beta1 on the normal patellar tendon and the characteristics of remaining tendon after the partial resection of hypertrophic one were investigated. MATERIALS AND METHODS: TGF-beta1 was injected into the right patellar tendon of mature rats weekly for 3 weeks. Histological study, biomechanical analysis and the transmission electron microscopic evaluation were done. Half of hypertrophic tendon was resected at 4 weeks after the last injection and the same analyses were RESULTS: TGF-beta1 treated tendon increased in cross sectional area but decreased significantly in maximum tensile stress. The hypertrophic tissue was mainly composed of small collagen fibrils. After the partial resection of hypertrophic tendon, there was no significant difference in maximum tensile stress between remaining and control tendons. There were relatively larger collagen fibrils in the remaining tendon tissue than in non-resected hypertrophic one. CONCLUSION: Local injection of TGF-beta1 induced the hypertrophy of normal tendon. After the partial resection of hypertrophic tendon, the remaining one showed the more similar biomechanical properties to normal one.

Laser scanning confocal microscope study of wet bonding interface on different dentin bonding surfaces / 实用口腔医学杂志

Objective: To study the bonding interface characteristic of five wet bonding systems while bonding on different dentin bonding surfaces. Methods: Rhodamine B was used to label five adhesives(OptiBond Sol o,Single Bond,Gluma One-Bond,Bond-1 and One-Step) in consistency of 0.1%, an d the bonding interface of the 5 wet bonding systems on dry or wet dentin surfa ces was observed with laser scanning confocal microscope. Results: All five bonding systems could infiltrate well into dentin bonding interface when bonding on wet dentin surface. The fluorescence confocal images gave eviden ce of the adhesives penetrated into the widened tubules, lateral tubules and dem ineralized peritubular dentin. Little discontinuity in dentin tubular was observ ed in the images, especially in those of alcohol-water-based adhesives. When b onded in dry dentin surface, the hybrid thickness of acetone-based adhesives de creased significantly. Conclusion: The penetration ability of ad hesives may be reduced significantly on dry dentin surface.

Ultrastructual analysis of the fibrous layer of condyle in the rat temporomandibular joint with ageing

Interaction of Attachment Complex and Anchoring Fibrils following Corneal Culture

This study was performed to elucidate the structural changes of the attachment complex in the cultured cornea. The three normal corneal tissues were used in this study. The ultrastructural changes of the attachment complex were observed by electron microscopy in one corneal tissue which was not cultured and cultured for 6 days and two corneal tissues which were cultured 10 days and 20 days, respectively. The cornea cultured for 6 days showed changes in the electron density of the hemidesmosome. The basal lamina was focally detached from the cytoplasmic wall of the basal epithelial cells in the cornea cultured for 10 days. The anchoring fibrils within the nuded corneal stroma, which was cultured for 20 days, were markedly decreased in number. These findings suggest that the normal basal epithelial cell, hemidesmosomes and basal lamina might be the essential factors to maintain the networks of normal anchoring fibrils in corneal stroma.