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Sample records for hyaline membrane formation

  1. Pulmonary Changes in Preterm Neonates with Hyaline Membrane Disease (a Clinicomorphological Study

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    A. M. Golubev

    2009-01-01

    Full Text Available Objective: to reveal lung morphological changes in preterm neonatal infants with hyaline membrane disease (HMD in the use of exogenous surfactants and artificial ventilation. Materials and methods. Case histories and autopsy protocols were analyzed in 90 preterm neonates who had died from severe respiratory failure. All the neonates were divided into 4 groups: 1 20 (22.2% infants who had received the exogenous surfactant Curosurf in the combined therapy of HMD; 2 19 (21.1% babies with HMD who had taken Surfactant BL; 3 25 (27.8% surfactant-untreated infants who had died from HMD; 4 26 (28.9% very preterm neonates with extremely low birth weight who had died within the first hour of life. The lungs were histologically and morphometrically examined. Results. The study demonstrated the specific course of HMD when exogenous surfactants and artificial ventilation were used. The contributors to the development of the disease are intranatal amniotic fluid aspiration and intranatal fetal hypoxia. Conclusion. Artificial ventilation and the use of exogenous surfactants do not block the generation of hyaline membranes. The latter differ in formation time, form, and location. The differences in a cell response to hyaline membranes were found in the neonatal infants receiving exogenous surfactants. The characteristic morphological signs of the disease for all the neonates enrolled in the study are alveolar and bronchial epithelial damages and microcirculatory disorders. Key words: preterm neonatal infants, hyaline membrane disease, exogenous surfactants, artificial ventilation, histology, morphometry.

  2. OUTCOME OF VENTILATION IN HYALINE MEMBRANE DISEASE: THE INDIAN EXPERIENCE

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    Nayana Prabha

    2016-06-01

    Full Text Available OBJECTIVE To study the short-term outcome of both preterm and term babies requiring assisted ventilation for hyaline membrane disease and report the complications contributing to morbidity and mortality of these patients from a regional medical college with limited resources. DESIGN Retrospective file review. SETTING Regional Medical College. PARTICIPANTS All babies ventilated for HMD over a 6-year period from June 2008 to June 2014. OUTCOME MEASURES Outcome of ventilation and factors contributing to mortality. RESULTS Out of 100 babies with hyaline membrane disease who were ventilated, 82% survived. Increasing gestational age and birth weight was associated with survival. The commonest complication was shock (77% and the commonest cause of mortality was septicaemia (77%. Septicaemia, Disseminated Intravascular Coagulation (DIC and pulmonary haemorrhage were significantly more common complications babies who died (p<0.05. Binary logistic regression analysis showed that DIC (Odds ratio 5.2 [Confidence intervals (C.I. 1.1-27.1] and pulmonary haemorrhage (OR 18 [1.72-45.2] to be predictors of mortality. The incidence of intraventricular haemorrhage was 1% and that of pneumothorax was 2%. The initial peak inspiratory pressure administered was significantly lower (p=0.033 and maximum peak end expiratory pressure was significantly higher in those who expired (p=0.027. CONCLUSION Outcome of ventilation for hyaline membrane disease improves with increasing gestational age and birth weight. The commonest cause of mortality and morbidity were septicaemia and shock respectively.

  3. Hyaline membrane disease (HMD: the role of the perinatal pathologist

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    Giorgia Locci

    2014-06-01

    Full Text Available Hyaline membrane disease (HMD, the pathologic correlate of respiratory distress syndrome (RDS of the newborn, is an acute lung disease of premature infant caused by inadequate amounts of surfactant. Decreased surfactant results in insufficient surface tension in the alveolus during expiration, leading to atelectasis, decreased gas exchange, severe hypoxia and acidosis. HMD predominantly occurs in infants younger than 32 weeks of gestation and weighing less than 1,200 g. In the interpretation of perinatal lung pathology, it is necessary to consider the development of the immature lung, particulary in the third trimester. Microscopically HMD is characterized by the occurrence of dilated terminal and respiratory bronchioles and of alveolar ducts lined by acellular eosinophilic hyaline membranes. The membranes are composed of necrotic alveolar lining cells, amniotic fluid constituents and fibrin. Retinopathy of prematurity and bronchopulmonary dysplasia are late complications of RDS that usually occur in infants who weigh less than 1,500 g and were maintained on a mechanical respiration more than 6 days. Here a pratical approach to a microscopic analysis of the lung in newborns died with the clinical setting of RDS is presented. The most important pathological findings for a complete clinical pathological diagnosis are: the evaluation of the architectural lung development; the endothelial cell lesions; the interstitial edema; the occurrence of disseminated intravascular coagulation; the presence of associated inflammatory lesions. The usefulness of some immunohistochemical stains is also underlined, including anti-surfactant, anti-smooth muscle actin and anti-CD31 to better evaluate surfactant production, pulmonary artery maturation and endothelial cell damage, respectively. Finally, the prevalent role of endothelial dysfunction and endothelial barrier loss is underlined, representing a major pathological event in the deposition of HMD

  4. Hyaline membrane disease or respiratory distress syndrome? A new approach for an old disease

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    Lidia Grappone

    2014-06-01

    Full Text Available The term “hyaline membrane disease” refers to the histological aspect of the most frequent pulmonary pathology in preterm newborn patients. The lung of the preterm baby is morphologically and functionally immature. Surfactant deficiency in the immature lungs causes alveolar instability and collapse, capillary edema and the formation of hyaline membrane. Thus, the hyaline membranes are epiphenomena and are not the cause of respiratory failure in infants with immature lungs. This definition is presently used to indicate surfactant deficit alone and should not be used for other causes of respiratory distress. Clinicians prefer to talk of “respiratory distress syndrome” (RDS. Improvement in neonatal treatment has changed the natural course of the illness, its clinical and radiological features and has enabled extremely low birth weight newborns (ELBW to survive. Alveoli paucity and pulmonary interstitial thickness in ELBW impair gas exchange and may necessitate prolonged ventilation treatment, increasing the risk of ventilator-induced lung injury (VILI and bronchopulmonary dysplasia (BPD. RDS, therefore, is a complex illness where pulmonary immaturity and surfactant deficit play a role together with other pathological conditions that determine the course of the illness and both short and long-term results. Proceedings of the International Course on Perinatal Pathology (part of the 10th International Workshop on Neonatology · October 22nd-25th, 2014 · Cagliari (Italy · October 25th, 2014 · The role of the clinical pathological dialogue in problem solving Guest Editors: Gavino Faa, Vassilios Fanos, Peter Van Eyken

  5. Formation of Hyaline Cartilage Tissue by Passaged Human Osteoarthritic Chondrocytes.

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    Bianchi, Vanessa J; Weber, Joanna F; Waldman, Stephen D; Backstein, David; Kandel, Rita A

    2017-02-01

    When serially passaged in standard monolayer culture to expand cell number, articular chondrocytes lose their phenotype. This results in the formation of fibrocartilage when they are used clinically, thus limiting their use for cartilage repair therapies. Identifying a way to redifferentiate these cells in vitro is critical if they are to be used successfully. Transforming growth factor beta (TGFβ) family members are known to be crucial for regulating differentiation of fetal limb mesenchymal cells and mesenchymal stromal cells to chondrocytes. As passaged chondrocytes acquire a progenitor-like phenotype, the hypothesis of this study was that TGFβ supplementation will stimulate chondrocyte redifferentiation in vitro in serum-free three-dimensional (3D) culture. Human articular chondrocytes were serially passaged twice (P2) in monolayer culture. P2 cells were then placed in high-density (3D) culture on top of membranes (Millipore) and cultured for up to 6 weeks in chemically defined serum-free redifferentiation media (SFRM) in the presence or absence of TGFβ. The tissues were evaluated histologically, biochemically, by immunohistochemical staining, and biomechanically. Passaged human chondrocytes cultured in SFRM supplemented with 10 ng/mL TGFβ3 consistently formed a continuous layer of articular-like cartilage tissue rich in collagen type 2 and aggrecan and lacking collagen type 1 and X in the absence of a scaffold. The tissue developed a superficial zone characterized by expression of lubricin and clusterin with horizontally aligned collagen fibers. This study suggests that passaged human chondrocytes can be used to bioengineer a continuous layer of articular cartilage-like tissue in vitro scaffold free. Further study is required to evaluate their ability to repair cartilage defects in vivo.

  6. Radiologic and histologic features of hyaline membrane diseases of the newbone

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    Baek, Seung Yon; Choi, Kyung Hee; Suh, Jeong Soo; Rhee, Chung Sik; Kim, Hee Seup [Ewha Womans University College of Medicine, Seoul (Korea, Republic of)

    1984-12-15

    This study represents the radiologic, histologic features and clinical analysis of hyaline membrane diseases in 47 newbone infants who were delivered in Ewha Womans Univ. Hospital and expired caused by respiratory distress and confirmed by autopsy, during Jan. 1981 to June. 1984. The results were as follows: 1. Classification of radiographic stage (by Wolfson's criteria); Stage III (34.1%) was the most frequent. 2. Male to female ratio was 2.4 : 1. 3. Method of delivery; Cesarean section (44.7%) was the highest frequency, compared with percent of cesarean section to total delivery (29.0%) 4. Distribution of birth weight; 1.0-2.0 kg (48.9%) was the most frequent. 5. Distribution of gestational period; 32-36 weeks (29.8%) was the most frequent. 6. Complication; pulmonary hemorrhage (31.9%) was the most frequent, in order, subarachnoid hemorrhage and pneumothorax were followed. 7. Final diagnosis of hyaline membrane diseases was based on histo-pathologic diagnosis.

  7. Changes of cerebral hemodynamics following the administration of surfactant in the hyaline membrane disease of prematurity

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    Yoo, Jeong Hyun; Kim, Kyung Hee [Ewha Womans University College of Medicine, Seoul (Korea, Republic of)

    2000-09-15

    To evaluate the changes of cerebral blood flow velocity according to the time, before and after surfactant administration in hyaline membrane disease using Doppler ultrasonography. The patients were 15 premature babies who were clinically and radiologically diagnosed HMD. The ratio of male : female was 11:4, the mean gestational age was 30.1 {+-} 2.5 wks, mean body weight was 1.4 {+-} 0.6 kg,mean Apgar score at 5 min was 6.28, and type of delivery was C-section : vaginal delivery 9.6. Before and after, 10 mm, 30 min, 1 hr, 6 hr, 12 hr, 1 day, 3 day, 5 day and 7 day after surfactant administration, peak systolic and end-diastolic cerebral blood flow velocity (PSFV, EDFV) and resistive index (RI) were estimated by Doppler ultrasonography measuring MCA flow velocity using temporal window. The averages of all data according to the time were obtained and analyzed statistical significance. For the evaluation of the clinical status systemic BP, FiO2, pH, and respiratory rate were also checked according to the same time. The clinical status of FiO2, metabolic acidosis, and tachypnea was significantly improved after surfactant administration. There was no significant change of cerebral blood flow velocity (PSFV, EDFV) after the surfactant administration. The change of RI was nor statistically significant. The changes of the systemic BP had no significant changes. In spite of clinical improvement, there were no significant increases of cerebral blood flow velocity and changes of RI after surfactant administration in hyaline membrane disease.

  8. Roentgenographic findings in hyaline membrane disease treated with exogenous surfactant: comparison with control group

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    Lee, Sun Kyoung; Lim, Chae Ha; Lim, Woo Young; Kim, Young Sook; Byen, Ju Nam; Oh, Jae Hee; Kim, Young Chul [Chosun Univ. College of Medicine, Kwangju (Korea, Republic of)

    1997-01-01

    To compare, with the use of chest radiographic findings, improvement and complications in newborns treated with exogenous surfactant for hyaline membrane disease (HMD), and an untreated control group. Thirty-six patients with HMD were randomly assigned to a control group (n=18) or surfactant treated group (n=18). As part of an initial evaluation of their pulmonary status, we then performed a retrospective statistical analysis of chest radiographic findings obtained in exogenous surfactant treated and untreated infants within the first 90 minutes of life. Subsequent examinations were performed at less than 24 hours of age. Chest radiograph before treatment showed no significant differences between the two groups, but significant improvement was noted in the surfactant treated group, in contrast to the control group. The most common chest radiographic finding after surfactant administration was uniform (n=15) or disproportionate (n=2) improvement of pulmonary aeration. Patent ductus arteriosus developed in three treated neonates and in four cases in the control group. Air leak occurred in three cases in the treated group and in five cases in the control group. In one treated patient pulmonary hemorrhage developed and intracranial hemorrhage occurred in three treated neonates and in four cases in the control group. Bronchopulmonary dysplasia was developed in 6 cases of treated group and 3 cases of control group. A chest radiograph is considered to be helpful in the evaluation of improvement and complications of HMD in infants treated with surfactant.

  9. Deleted in Malignant Brain Tumors 1 (DMBT1 is present in hyaline membranes and modulates surface tension of surfactant

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    Griese Matthias

    2007-10-01

    Full Text Available Abstract Background Deleted in Malignant Brain Tumors 1 (DMBT1 is a secreted scavenger receptor cysteine-rich protein that binds various bacteria and is thought to participate in innate pulmonary host defense. We hypothesized that pulmonary DMBT1 could contribute to respiratory distress syndrome in neonates by modulating surfactant function. Methods DMBT1 expression was studied by immunohistochemistry and mRNA in situ hybridization in post-mortem lungs of preterm and full-term neonates with pulmonary hyaline membranes. The effect of human recombinant DMBT1 on the function of bovine and porcine surfactant was measured by a capillary surfactometer. DMBT1-levels in tracheal aspirates of ventilated preterm and term infants were determined by ELISA. Results Pulmonary DMBT1 was localized in hyaline membranes during respiratory distress syndrome. In vitro addition of human recombinant DMBT1 to the surfactants increased surface tension in a dose-dependent manner. The DMBT1-mediated effect was reverted by the addition of calcium depending on the surfactant preparation. Conclusion Our data showed pulmonary DMBT1 expression in hyaline membranes during respiratory distress syndrome and demonstrated that DMBT1 increases lung surface tension in vitro. This raises the possibility that DMBT1 could antagonize surfactant supplementation in respiratory distress syndrome and could represent a candidate target molecule for therapeutic intervention in neonatal lung disease.

  10. 新生儿肺透明膜病的护理%Nursing care for neonates with hyaline membrane disease

    Institute of Scientific and Technical Information of China (English)

    黎婷; 彭间英; 罗冰贤

    2013-01-01

    目的 总结讨论新生儿肺透明膜病的护理体会,加强护理意识与方法.方法 对我院收治的82例新生儿肺透明膜病患儿进行系统的回顾性分析,对其护理方法进行总结.结果 经过采取综合护理后大部分患儿康复出院,少数患儿发生并发症,其中4例因肺出血合并弥漫性血管内凝血(DIC)死亡.结论 在积极治疗新生儿肺透明膜病的过程中,采取行之有效的综合护理可显著降低其病死率,提高生存率.%Objective To summarize the nursing experience on neonates with hyaline membrane disease,and to strengthen nursing consciousness and measures.Methods The data on 82 neonates with hyaline membrane disease who had been treated in our hospital were retrospectively analyzed.The nursing methods were summarized.Results After receiving comprehensive nursing care,most of the infants were discharged with rehabilitation.Complications occurred in a few of patients,4 of whom were dead due to pulmonary hemorrhage complicated by disseminated intravascular coagulation (DIC).Conclusions Effective nursing care can significantly reduce the mortality rate and improve the survival rate in the treatment of neonates with hyaline membrane disease.

  11. Hyaline cartilage formation and tumorigenesis of implanted tissues derived from human induced pluripotent stem cells.

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    Saito, Taku; Yano, Fumiko; Mori, Daisuke; Kawata, Manabu; Hoshi, Kazuto; Takato, Tsuyoshi; Masaki, Hideki; Otsu, Makoto; Eto, Koji; Nakauchi, Hiromitsu; Chung, Ung-il; Tanaka, Sakae

    2015-01-01

    Induced pluripotent stem cells (iPSCs) are a promising cell source for cartilage regenerative medicine. Meanwhile, the risk of tumorigenesis should be considered in the clinical application of human iPSCs (hiPSCs). Here, we report in vitro chondrogenic differentiation of hiPSCs and maturation of the differentiated hiPSCs through transplantation into mouse knee joints. Three hiPSC clones showed efficient chondrogenic differentiation using an established protocol for human embryonic stem cells. The differentiated hiPSCs formed hyaline cartilage tissues at 8 weeks after transplantation into the articular cartilage of NOD/SCID mouse knee joints. Although tumors were not observed during the 8 weeks after transplantation, an immature teratoma had developed in one mouse at 16 weeks. In conclusion, hiPSCs are a potent cell source for regeneration of hyaline articular cartilage. However, the risk of tumorigenesis should be managed for clinical application in the future.

  12. 鼻塞式CPAP治疗新生儿肺透明膜病疗效观察%Efficacy of Hyaline Membrane Disease Nasal CPAP Treatment

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    艾力甫

    2015-01-01

    目的:观察鼻塞式CPAP(NCPAP)治疗新生儿肺透明膜病的疗效。方法对20例早期新生儿肺透明膜病进行X线检查,根据血气分析结果调整呼吸机参数。结果20例患儿放弃治疗1例,转上级医院治疗1例,余18例顺利撤除鼻塞式CPAP。结论鼻塞式CPAP治疗早期新生儿肺透出明膜病能明显的提高治疗效果,对早产儿非常适用。%Objective To observe the nasal CPAP (NCPAP)therapy hyaline membrane disease.Methods 20 cases of early neonatal hyaline membrane disease,X-ray inspection,adjustment of ventilator parameters based on the results of blood gas analysis.Results 20 patients gave up treatment one case,turn higher hospital one case,more than 18 cases of successful removal of nasal CPAP.Conclusion Nasal CPAP treatment early neonatal lung disease,revealed a clear film can significantly improve the therapeutic ef ect,very suitable for preterm children.

  13. 新生儿肺透明膜病的多层螺旋CT诊断%The MSCT Diagnosis of Neonatal Hyaline Membrane Disease

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    韦学; 谭俊扬; 胡琪琳; 廖保荣

    2011-01-01

    Objective To explore the Spiral CT signs of neonatal hyaline membrane disease .Analysis its Pathogenesis and clinical manifestation through literature review in order to improve the understanding of the disease. Methods Analyze our hospital 18 cases of neonatal hyaline membrane disease from May 2008 to March 2011 especially focus on the multislice CT imaging features. Results Grinding glass phenomenon of double lung among all cases, including air-filled bronchi imaging levy in 12 cases, white lung change 1 case, pneumothorax 4 cases, pneumomediastinum 2 cases, among them, including Neck soft tissue emphysema 2 cases, pulmonary hemorrhage 1 case. Conclusion The MDCT performance of neonatal hyaline membrane disease has certain characteristic, and can supply the evidence for imaging diagnosis this lesion.%目的 探讨新生儿肺透明膜病的螺旋CT征象特点,分析其发病机制及临床表现,通过复习文献,提高对该病的认识.方法 分析我院自2008年5月至2011年3月具有完整资料的肺透明膜病18例,着重分析多层螺旋CT对其肺部的病灶显示能力及影像学特征.结果 本组病例中全部出现双肺透亮度降低的磨玻璃样影及小颗粒样影,其中合并出现支气管充气造影征12例,白肺改变1例,气胸4例,纵隔气肿2例,其中1例合并颈部软组织内气肿.合并肺出血1例.结论 新生儿肺透明膜病多层螺旋CT表现有一定的特征性,可为临床提供重要的影像学依据.

  14. The effect of polymer size and charge of molecules on permeation through synovial membrane and accumulation in hyaline articular cartilage.

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    Sterner, B; Harms, M; Wöll, S; Weigandt, M; Windbergs, M; Lehr, C M

    2016-04-01

    The treatment of joint related diseases often involves direct intra-articular injections. For rational development of novel delivery systems with extended residence time in the joint, detailed understanding of transport and retention phenomena within the joint is mandatory. This work presents a systematic study on the in vitro permeation, penetration and accumulation of model polymers with differing charges and molecular weights in bovine joint tissue. Permeation experiments with bovine synovial membrane were performed with PEG polymers (6-200 kDa) and methylene blue in customized diffusion chambers. For polyethylene glycol, 2-fold (PEG 6 kDa), 3-fold (PEG 10 kDa) and 13-fold (PEG 35 kDa) retention by the synovial membrane in reference to the small molecule methylene blue was demonstrated. No PEG 200 kDa was found in the acceptor in detectable amounts after 48 h. This showed the potential for a distinct extension of joint residence times by increasing molecular weights. In addition, experiments with bovine cartilage tissue were conducted. The ability for positively charged, high molecular weight chitosans and HEMA-Co-TMAP (HCT) polymers (up to 233 kDa) to distribute throughout the entire cartilage matrix was demonstrated. In contrast, a distribution into cartilage was not observed for neutral PEG polymers (6-200 kDa). Furthermore, the positive charge density of different compounds (chitosan, HEMA-Co-TMAP, methylene blue, MSC C1 (neutral NCE) and MSC D1 (positively charged NCE) was found to correlate with their accumulation in bovine cartilage tissue. In summary, the results offer pre-clinical in vitro data, indicating that the modification of molecular size and charge of a substance has the potential to decelerate its clearance through the synovial membrane and to promote accumulation inside the cartilage matrix. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Imaging Analysis of Pulmonary Hyaline Membrane Disease in Newborns%新生儿肺透明膜病的影像诊断

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    韩海; 欧阳大军; 曾晓春; 朱凯帮; 吕铭; 黄婉红

    2011-01-01

    目的 探讨新生儿肺透明膜病的影像特征,提高对本病的认识和早期诊断能力.方法 回顾性分析经临床及病理证实的105例新生儿肺透明膜病的X线表现.结果 本组105例中27例表现为肺野肺透光度下降及呈弥漫颗粒状阴影;33例表现为肺野透光度减低、斑片状密度阴影;26例肺野透光度明显下降,广泛斑片状阴影,心缘及膈面模糊;19例肺野呈均匀致密影,称为"白肺" .其中合并肺炎24例,肺出血13例,动脉导管未闭19例,气胸7例,缺氧缺血性脑病(HIE)11例.结论 新生儿肺透明膜病的影像表现各种各样,其中磨玻璃征、肺纹理被掩盖不能分辨和支气管充气征在本病中具有特征性表现.普通X线检查和结合临床是诊断新生儿肺透明膜病的可靠方法.%Objective To investigate the imaging features of pulmonary hyaline membrane disease ( HMD) in newborns and to improve the early diagnoscic ability. Methods X - ray findings of 105 newborns with clinically and pathologically proved HMD were analyzed retrospectively. Results Twenty - seven casea of 105 newboms with HMD had fine reticular changing and diffuse granular opacities in the lung field,33 cases had decreased hyalinization of lung field , mottling shadows with high density, and 26 cases cardiae border and diaphragmatic face hazy. ninteen cases presented as "white lung , of whom, 24 cases were complicated with pneumonia,19 casea were complicated with pulmonary hemorrhage , and 13 cases had patent ductus arterious , 7 casea were complicated with pneumothorax and 11 cases hypoxic ischemic encephalopathy ( HIE) . Conclusion There are various images of HMD in newboms. Ground glass opacity of the whole lungs and pulmonary grain concealed and the aerial bronchogram are three charactenstic findings of HMD. Conventional X - ray chest radiography combining the clinical Bymptoms ia considered the most reliable diagnostic tool in HMD diagnosis in newborns.

  16. Surgical correction of joint deformities and hyaline cartilage regeneration

    National Research Council Canada - National Science Library

    Vinokurov, Vyacheslav Alexandrovich; Norkin, Igor Alekseevich

    2015-01-01

    Aim. To determine a method of extra-articular osteochondral fragment formation for the improvement of surgical correction results of joint deformities and optimization of regenerative conditions for hyaline cartilage...

  17. 新生儿肺透明膜病及湿肺病的分类决策诊断%Classification decision tree in differentiating wet lung disease from hyaline membrane disease of newborns

    Institute of Scientific and Technical Information of China (English)

    施莉丽; 吴伟军; 张骥; 罗剑锋

    2012-01-01

    Objective To establish classification and regression tree for differentiating wet lung disease from hyaline membrane disease, and to discuss the diagnostic value of the relative clinical presentations and x-ray findings. Methods Forty-three cases of hyaline membrane disease and forty-eight cases of wet lung disease of newborns were analyzed retrospectively. Six clinical presentations and seven X-ray findings were collected as predictors. A classification tree was established to distinguish the two diseases. In the observing test, one senior radiologist was independently presented with clinical information and X-ray findings without knowing The correct diagnosis. Meanwhile, statistic analysis was used to compare the diagnostic agreement of CART model and the senior radiologist. Results The model of CART, in which there were nine diagnostic paths, could reliably diagnose wet lung disease from hyaline membrane disease. CART showed that air bronchogram, gestational weeks, ground glass appearance and horizontal fissure were of important diagnostic value. Kappa analysis showed the diagnostic agreement of CART and the senior radiologist was 0. 553 (wet lung disease, medium agreement) and 0. 628 (hyaline membrane disease, high agreement). Conclusion CART can provide a high accuracy in differentiating wet lung disease from hyaline membrane disease. The sign of air bronchogram, gestational weeks, ground glass appearance, and horizontal fissure are important diagnostic predictors.%目的 应用分类决策树(classification and regression tree,CART)算法构建胸片鉴别新生儿透明膜病及湿肺病的诊断模型,探讨多种临床及影像因素对肺透明膜病及湿肺病的诊断价值.方法 病例为2008年1月~2010年12月间经过临床及影像证实的新生儿肺透明膜病43例、湿肺病48例.分别提取和上述两种疾病有关的6个临床指标和7个影像学指标作为CART预测新生儿肺透明膜病及湿肺病的变量.用CART建立两

  18. 新生儿肺透明膜病的计算机X线摄影表现与临床分析%Clinical analysis and computed radiography showed of pulmonary hyaline membrane disease of the newborn

    Institute of Scientific and Technical Information of China (English)

    刘正奎

    2014-01-01

    目的:探讨新生儿肺透明膜病的计算机X线摄影表现与临床分析。方法:2011年1月-2013年12月收治使用计算机X线摄影进行诊断的新生儿肺透明膜病患儿80例,根据新生儿肺透明膜病X线的表现,对X线与临床因素之间的关系进行分析。结果:80例新生儿肺透明膜病中,Ⅰ级、Ⅱ级、Ⅲ级、Ⅳ级分别有8例、21例、43例、8例,所占比例分别是10.00%、26.25%、53.75、10.00%。52例患儿出现并发症,并发症发生率65%,22例肺炎,8例缺血缺氧脑病,2例颅内出血,4例肺出血,6例气胸,7例胸腔积液,2例先天性心脏病,1例支气管肺发育不良。其中13例患儿死亡,死亡率20%。结论:新生儿肺透明膜病的病情发展快,且多发合并症,死亡率较高,因此需要尽早确诊,以得到及时有效的治疗,尤其在早产儿、低体重儿中更应注意此病。%Objective:To investigate the clinical analysis and computed radiography showed of pulmonary hyaline membrane disease of the newborn.Methods:80 newborn with hyaline membrane disease who diagnosed by the computer X-ray photography were selected from January 2011 to December 2013.We analyzed the relationship between X-ray and clinical factors according to the x-ray performance of neonatal hyaline membrane disease.Results:80 cases of neonatal pulmonary hyaline membrane disease, grade Ⅰ, Ⅱ, Ⅲ, Ⅳ there were 8 cases,21 cases,43 cases,8 cases respectively;the proportions were 10.00% ,26.25% ,53.75% , 10.00% respectively.52 cases(65%)had complications;22 cases of pneumonia;8 cases of hypoxic ischemic encephalopathy;2 cases of intracranial hemorrhage;4 cases with pulmonary hemorrhage;6 cases of pneumothorax;pleural effusion in 7 cases;2 cases of congenital heart disease;1 case of bronchopulmonary dysplasia.Among them 13 cases died,and the mortality was 20%.Conclusion:Neonatal hyaline membrane disease develops fast,and has many complications

  19. Juvenile hyaline fibromatosis.

    Science.gov (United States)

    Larralde, M; Santos-Muñoz, A; Calb, I; Magariños, C

    2001-01-01

    Juvenile hyaline fibromatosis (JHF) is a rare autosomal recessive disease with onset in infancy or early childhood. It is characterized by papulonodular skin lesions, soft tissue masses, gingival hypertrophy, and flexion contractures of the large joints. The light and electron microscopic features are very distinctive. Here we report an 8-month-old boy with characteristic stiffness of the knees and elbows and pink confluent papules on the paranasal folds, and periauricular and perianal regions. He also had hard nodules all over the scalp and around the mouth, and severe gingival hypertrophy. Histologic and ultrastructural features were typical of JHF. Clinical features, pathology, and physiology are discussed.

  20. Hyaline fibromatosis syndrome: cutaneous manifestations*

    Science.gov (United States)

    Marques, Silvio Alencar; Stolf, Hamilton Ometto; Polizel, Juliana Ocanha; Munhoz, Tânia; Brandão, Marcela Calixto; Marques, Mariangela Esther Alencar

    2016-01-01

    Hyaline fibromatosis syndrome is the current name for clinical manifestations of diseases previously known as “infantile systemic hyalinosis” and “juvenile hyaline fibromatosis”. The authors report representative clinical cases of each one of the above subtypes with emphasis on cutaneous manifestations and difficulties for early diagnosis in this syndrome, essentially of multidisciplinary approach. PMID:27192526

  1. 基于STATA固尔苏治疗肺透明膜病的系统评价%Systematic Evaluation of Curosurf for Treating Hyaline Membrane Disease Using STATA

    Institute of Scientific and Technical Information of China (English)

    陈友生; 余超; 胡炜华

    2013-01-01

    目的 基于STATA对固尔苏治疗肺透明膜病的疗效进行系统评价.方法 通过Cochrane图书馆(2011年第4期)的临床对照试验中心资料库、PubMed、万方、维普、CNKI及中国生物医学文献系统(手工检索新生儿疾病会议论文和内部资料等灰色文献)检索固尔苏治疗肺透明膜病的随机对照试验文献.利用Revman 5.1.4.0软件进行Meta分析,并用STATA12.0软件进行发表偏倚的评价.结果 共纳入10篇中文文献.合并分析结果显示,固尔苏治疗组治疗28 d内的病死率与对照组相比,差异有统计学意义(RR=0.35,95%CI 0.23~0.54).结论 固尔苏能降低肺透明膜病的病死率,对治疗肺透明膜病有一定的疗效.%Objective To systematically evaluate the effect of Curosurf on hyaline membrane disease using STATA. Methods The literature was searched for randomized controlled trials of Curosurf to treat hyaline membrane disease using central repository in controlled clinical trials of controlled clinical trials (Cochrane Collaboration,No. 4,2011) ,PubMed, Wanfang Data,CQVIP, CNKI and CBMD ISC. Revman 5. 1. 4. 0 software was used to perform Meta-analysis and STATA12. 0 software was used to evaluate publication bias. Results A total of 10 Chinese literatures were collected. The combined analysis results showed that Curosurf treatment (<28 days) significantly decreased the mortality compared with control group(RR = 0. 35,95% CI0. 23-0. 54). Conclusion The treatment with Curosurf can reduce the mortality and may have a demonstrable curative effect on hyaline membrane disease.

  2. Juvenile hyaline fibromatosis

    Directory of Open Access Journals (Sweden)

    Jayashree Krishnamurthy

    2011-01-01

    Full Text Available Juvenile hyaline fibromatosis is a rare, autosomal-recessive disease characterized by papular and nodular skin lesions, gingival hyperplasia, joint contractures and bone involvement in variable degrees. It is a connective tissue disorder with aberrant synthesis of glycosaminoglycans by fibroblasts. We report a 5-year-old female born of first-degree consanguineous marriage who presented with multiple, recurrent, painless, variable-sized nodules. Fine needle aspiration cytology smears and the subsequent histopathological examination from the nodules showed benign spindle cells in a Periodic acid Schiff-positive myxoid background. The disease has a relentlessly progressive course, with most patients surviving only up to the 4 th decade. As of now, there is no specific treatment for this disorder. Genetic counseling is essential to explain to parents about a 25% chance of having a diseased baby in any pregnancy. With the gene being mapped recently, techniques for antenatal diagnosis are likely to be established.

  3. Comparative analysis of hyaline membrane disease with X-ray films and CT diagnosis%新生儿肺透明膜病X线片与CT诊断对照分析

    Institute of Scientific and Technical Information of China (English)

    林华云; 林云亮

    2012-01-01

    目的 对新生儿肺透明膜病X线片和CT诊断结果进行比较分析,并探讨其应用.方法 选取2009年11月~2011年11月于我院诊治的新生儿肺透明膜病患儿50例,对照其临床治疗过程中的X线片与CT影像学资料,观察分析诊断结果.结果 新生儿肺透明膜病的典型病症包括胸片表现的细颗粒状、网格状、支气管充气征以及两肺野透亮度减低等,并发症包括肺出血、肺炎和气胸等.分析表明,肺部病变检出率CT扫描与X线片二者比较差异有高度统计学意义(P < 0.01);并发症检出率CT扫描与X线片二者比较差异有统计学意义(P < 0.05).结论 X线片与CT对新生儿肺透明膜病的诊断是相互补充的,对临床高度可疑但X线片观察不能排除的患儿,应及时实施CT扫描,这对该疾病的鉴别诊断以及发现并发症等具有重要的指导性意义.%Objective To compare and analyse the results of the neonatal hyaline membrane disease X-ray films and CT diagnosis and explore its applications. Methods 50 cases hyaline membrane disease children from November 2009 to November 2011 in our hospital was selected, its clinical treatment in the process of X-ray film and CT imaging data was analysised, to the results of the diagnosis were observed and analyzed. Results Neonatal hyaline membrane disease typical symptoms, including chest X-ray performance of fine granular grid, air bronchogram, and two lung fields through the brightness to reduce and so on. The complications include pulmonary hemorrhage, pneumonia and pneumothorax. The analysis showed that the lung lesion detection rate of CT scan and X-ray film contrast the two was statistically significant (P < 0.01). Contrasted CT scan and X-ray film detection rate of complications, and the difference was statistically significant (P < 0.05). Conclusion X-ray films and CT complement each other hyaline membrane disease diagnosis, highly suspicious of clinical X-ray film observation can not

  4. Nanoscale Membrane Domain Formation Driven by Cholesterol

    DEFF Research Database (Denmark)

    Javanainen, Matti; Martinez-Seara, Hector; Vattulainen, Ilpo

    2017-01-01

    Biological membranes generate specific functions through compartmentalized regions such as cholesterol-enriched membrane nanodomains that host selected proteins. Despite the biological significance of nanodomains, details on their structure remain elusive. They cannot be observed via microscopic...... dipalmitoylphosphatidylcholine and cholesterol - the "minimal standard" for nanodomain formation. The simulations reveal how cholesterol drives the formation of fluid cholesterol-rich nanodomains hosting hexagonally packed cholesterol-poor lipid nanoclusters, both of which show registration between the membrane leaflets....... The complex nanodomain substructure forms when cholesterol positions itself in the domain boundary region. Here cholesterol can also readily flip-flop across the membrane. Most importantly, replacing cholesterol with a sterol characterized by a less asymmetric ring region impairs the emergence of nanodomains...

  5. BMP-2, hypoxia, and COL1A1/HtrA1 siRNAs favor neo-cartilage hyaline matrix formation in chondrocytes.

    Science.gov (United States)

    Ollitrault, David; Legendre, Florence; Drougard, Carole; Briand, Mélanie; Benateau, Hervé; Goux, Didier; Chajra, Hanane; Poulain, Laurent; Hartmann, Daniel; Vivien, Denis; Shridhar, Vijayalakshmi; Baldi, Alfonso; Mallein-Gerin, Frédéric; Boumediene, Karim; Demoor, Magali; Galera, Philippe

    2015-02-01

    Osteoarthritis (OA) is an irreversible pathology that causes a decrease in articular cartilage thickness, leading finally to the complete degradation of the affected joint. The low spontaneous repair capacity of cartilage prevents any restoration of the joint surface, making OA a major public health issue. Here, we developed an innovative combination of treatment conditions to improve the human chondrocyte phenotype before autologous chondrocyte implantation. First, we seeded human dedifferentiated chondrocytes into a collagen sponge as a scaffold, cultured them in hypoxia in the presence of a bone morphogenetic protein (BMP), BMP-2, and transfected them with small interfering RNAs targeting two markers overexpressed in OA dedifferentiated chondrocytes, that is, type I collagen and/or HtrA1 serine protease. This strategy significantly decreased mRNA and protein expression of type I collagen and HtrA1, and led to an improvement in the chondrocyte phenotype index of differentiation. The effectiveness of our in vitro culture process was also demonstrated in the nude mouse model in vivo after subcutaneous implantation. We, thus, provide here a new protocol able to favor human hyaline chondrocyte phenotype in primarily dedifferentiated cells, both in vitro and in vivo. Our study also offers an innovative strategy for chondrocyte redifferentiation and opens new opportunities for developing therapeutic targets.

  6. Gel layer formation on membranes in Membrane Bioreactors

    NARCIS (Netherlands)

    Van den Brink, P.F.H.

    2014-01-01

    The widespread application of membrane bioreactors (MBRs) for municipal wastewater treatment is hampered by membrane fouling. Fouling increases energy demand, reduces process performance and creates the need for more frequent (chemical) membrane cleaning or replacement. Membrane fouling in MBRs is k

  7. 早期微量喂养对新生儿肺透明膜病临床康复的影响%Effect of early micro feeding on the clinical rehabilitation of hyaline membrane disease

    Institute of Scientific and Technical Information of China (English)

    程书卿

    2015-01-01

    Objective: To investigate the effect of early micro feeding on the clinical rehabilitation of hyaline membrane disease(HMD).Methods:158 patients with HMD were treated.They were randomly divided into the observation group and the control group with 79 cases in each group.Patients in the observation group received the early minimal feeding treatment,while the control group adopted conventional feeding treatment.The clinical effect of two groups children were observed and compared. Results:The up to full enteral nutrition and recovery birth weight time,blood bilirubin peak,complicated with intrahepatic cholestasis,hospitalization days of the observation group were significantly better than those of the control group(P<0.05). Conclusion:Early trace feeding is helpful to HMD better transition to full enteral feeding,improve the children's weight effectively, reduce the incidence of cholestasis,improve the therapeutic effect.%目的:探讨早期微量喂养对新生儿肺透明膜病(HMD)临床康复的影响。方法:收治HMD患儿158例,随机分为观察组和对照组,各79例,观察组接受早期微量喂养治疗,对照组采取常规喂养治疗方式。观察比较两组患儿临床治疗效果。结果:观察组患儿达全量胃肠道营养时间、恢复出生体重时间、血胆红素峰值、并发胆汁淤积、住院天数等指标均显著优于对照组(P<0.05)。结论:早期微量喂养有利于HMD患儿更好地过渡到全量胃肠道喂养,能有效提高患儿体重,降低胆汁淤积发生率,提高治疗效果。

  8. Membrane Tether Formation on a Cell Surface with Reservoir

    Institute of Scientific and Technical Information of China (English)

    JIANG Yu-Qiang; GUO Hong-Lian; LIU Chun-Xiang; LI Zhao-Lin; CHENG Bing-Ying; ZHANG Dao-Zhong; JIA Suo-Tang

    2004-01-01

    @@ We propose a mathematical model to analyse the membrane tether formation process on a cell surface with reservoir. Based on the experimental results, the membrane reservoir density of breast cancer cell was obtained,p = 8.02. The membrane surface viscosity between membrane and environment η is 0.021(pN.s/μm3), and the static force F0 = 5.71 pN.

  9. Surgical correction of joint deformities and hyaline cartilage regeneration

    Directory of Open Access Journals (Sweden)

    Вячеслав Александрович Винокуров

    2015-12-01

    Full Text Available Aim. To determine a method of extra-articular osteochondral fragment formation for the improvement of surgical correction results of joint deformities and optimization of regenerative conditions for hyaline cartilage. Materials and Methods. The method of formation of an articular osteochondral fragment without penetration into the joint cavity was devised experimentally. More than 30 patients with joint deformities underwent the surgery. Results. During the experiments, we postulated that there may potentially be a complete recovery of joint defects because of hyaline cartilage regeneration. By destructing the osteochondral fragment and reforming it extra-articularally, joint defects were recovered in all patients. The results were evaluated as excellent and good in majority of the patients. Conclusion. These findings indicate a novel method in which the complete recovery of joint defects due to dysplastic genesis or osteochondral defects as a result of injuries can be obtained. The devised method can be used in future experiments for objectification and regenerative potential of hyaline cartilage (e.g., rate and volume of the reformed joints that regenerate, detection of cartilage elements, and the regeneration process.

  10. Genetics Home Reference: juvenile hyaline fibromatosis

    Science.gov (United States)

    ... Antaya RJ, Cajaiba MM, Madri J, Lopez MA, Ramirez MC, Martignetti JA, Reyes-Múgica M. Juvenile hyaline ... 103. Citation on PubMed Dowling O, Difeo A, Ramirez MC, Tukel T, Narla G, Bonafe L, Kayserili ...

  11. Formation and Regulation of Mitochondrial Membranes

    Directory of Open Access Journals (Sweden)

    Laila Cigana Schenkel

    2014-01-01

    Full Text Available Mitochondrial membrane phospholipids are essential for the mitochondrial architecture, the activity of respiratory proteins, and the transport of proteins into the mitochondria. The accumulation of phospholipids within mitochondria depends on a coordinate synthesis, degradation, and trafficking of phospholipids between the endoplasmic reticulum (ER and mitochondria as well as intramitochondrial lipid trafficking. Several studies highlight the contribution of dietary fatty acids to the remodeling of phospholipids and mitochondrial membrane homeostasis. Understanding the role of phospholipids in the mitochondrial membrane and their metabolism will shed light on the molecular mechanisms involved in the regulation of mitochondrial function and in the mitochondrial-related diseases.

  12. Aspirin inhibits formation of cholesterol rafts in fluid lipid membranes.

    Science.gov (United States)

    Alsop, Richard J; Toppozini, Laura; Marquardt, Drew; Kučerka, Norbert; Harroun, Thad A; Rheinstädter, Maikel C

    2015-03-01

    Aspirin and other non-steroidal anti-inflammatory drugs have a high affinity for phospholipid membranes, altering their structure and biophysical properties. Aspirin has been shown to partition into the lipid head groups, thereby increasing membrane fluidity. Cholesterol is another well known mediator of membrane fluidity, in turn increasing membrane stiffness. As well, cholesterol is believed to distribute unevenly within lipid membranes leading to the formation of lipid rafts or plaques. In many studies, aspirin has increased positive outcomes for patients with high cholesterol. We are interested if these effects may be, at least partially, the result of a non-specific interaction between aspirin and cholesterol in lipid membranes. We have studied the effect of aspirin on the organization of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) membranes containing cholesterol. Through Langmuir-Blodgett experiments we show that aspirin increases the area per lipid and decreases compressibility at 32.5 mol% cholesterol, leading to a significant increase of fluidity of the membranes. Differential scanning calorimetry provides evidence for the formation of meta-stable structures in the presence of aspirin. The molecular organization of lipids, cholesterol and aspirin was studied using neutron diffraction. While the formation of rafts has been reported in binary DPPC/cholesterol membranes, aspirin was found to locally disrupt membrane organization and lead to the frustration of raft formation. Our results suggest that aspirin is able to directly oppose the formation of cholesterol structures through non-specific interactions with lipid membranes. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Formation of the organic-inorganic proton exchange membrane

    Directory of Open Access Journals (Sweden)

    A.O. Maizelis

    2016-09-01

    Full Text Available The use of electrolyzers for the low-temperature water electrolysis with the solid polymer membrane is perspective for production of hydrogen using renewable energy sources. However, the high cost of membrane materials obstructs the mass commissioning of such electrolyzers. Most of the researches devoted to the technologies of membranes formation, alternative to Nafion®, deal only with organic materials. Aim: The aim of this research is to develop the method for formation of the competitive proton exchange membrane based on polyvinyl alcohol (PVA and inorganic hydrates. Materials and Methods: The hydrated oxide of tin was added to the 2...10% PVA solution, mixed and applied to inert base layer by layer for formation of the membrane. Then the membrane was separated from the base. The reinforcing mesh was used to improve mechanical properties of the membrane. The hydrated tin oxide was prepared by reaction of tin chloride and ammonium hydroxide solutions. Results: The conditions of formation of proton-exchange membranes based on polyvinyl alcohol and hydrated oxide of tin were investigated. The series of membranes containing 30, 50, 70, 80 and 90% of hydrated tin oxide are obtained. It is shown that a solid membrane film with the thickness over 100 μm can be obtained if the content of PVA exceeds 30%. It is shown that it is necessary to crosslink the chains of PVA in the resulting film. The structure of the obtained proton exchange membrane consists of PVA chains crosslinked by aldehyde, between which the globules of hydrated tin oxide are situated. The membrane conductivity is provided by both proton mobility of hydroxyl group of PVA and H3O+/H2O and OH–/H2O groups that are formed due to the partial dissociation of hydrated oxide on the surface of the globules.

  14. Macroscopic domain formation in the platelet plasma membrane

    DEFF Research Database (Denmark)

    Bali, Rachna; Savino, Laura; Ramirez, Diego A.;

    2009-01-01

    There has been ample debate on whether cell membranes can present macroscopic lipid domains as predicted by three-component phase diagrams obtained by fluorescence microscopy. Several groups have argued that membrane proteins and interactions with the cytoskeleton inhibit the formation of large d...

  15. A case of juvenile hyaline fibromatosis.

    Science.gov (United States)

    Yayli, Savaş; Uncu, Sibel; Alpay, Köksal; Yildiz, Kadriye; Cimşit, Gülseren; Bahadir, Sevgi

    2006-04-01

    Juvenile hyaline fibromatosis (JHF) is a rare, autosomally-recessive disease characterized by papulonodular skin lesions, soft tissue masses, joint contractures, gingival hypertrophy and osteolytic bone lesions. Its onset is in infancy or early childhood. The most commonly affected sites are the nose, chin, ears, scalp, back and knees. The accumulation of an amorphous, hyaline material is typical in the skin and the other organs. Herein, we report a 14-month-old boy who presented with confluent pink papules on the paranasal folds and the chin, and nodular lesions on the periauricular and perianal regions. He had gingival hypertrophy and contractures of the shoulders, knees and elbows. He also had third-degree consanguineous parents. Histopathological studies confirmed the diagnosis of JHF with the presence of increased numbers of fibroblasts embedded in a hyalinized connective tissue stroma.

  16. Transient domain formation in membrane-bound organelles undergoing maturation

    Science.gov (United States)

    Dmitrieff, Serge; Sens, Pierre

    2013-12-01

    The membrane components of cellular organelles have been shown to segregate into domains as the result of biochemical maturation. We propose that the dynamical competition between maturation and lateral segregation of membrane components regulates domain formation. We study a two-component fluid membrane in which enzymatic reaction irreversibly converts one component into another and phase separation triggers the formation of transient membrane domains. The maximum domain size is shown to depend on the maturation rate as a power law similar to the one observed for domain growth with time in the absence of maturation, despite this time dependence not being verified in the case of irreversible maturation. This control of domain size by enzymatic activity could play a critical role in regulating exchange between organelles or within compartmentalized organelles such as the Golgi apparatus.

  17. Laminations and microgranule formation in pediatric glomerular basement membranes.

    Science.gov (United States)

    Craver, Randall; Crespo-Salgado, Janice; Aviles, Diego

    2014-01-01

    Glomerular basement membrane (GBM) splitting, laminations, and microgranular formation are classically encountered with Alport disease, but can be found in other glomerular diseases. We found moderate to marked GBM laminations/microgranular formations in 51 of 724 (7%) pediatric diagnostic renal biopsies. These included 12 Alport disease, 12 thin basement membrane disease (TBM), 13 mesangial hypercellularity (MH), 6 focal segmental glomerulosclerosis (FSGS), and 8 other diseases. Follow-up demonstrated progression in most of the Alport disease and FSGS, as expected, but also in 40% of TBM and 30% of MH. Basement membrane laminations/microgranular formations are not specific for Alport disease, may represent a non-specific injury, and may herald a progressive clinical course.

  18. Membrane fouling in a membrane bioreactor (MBR): sludge cake formation and fouling characteristics.

    Science.gov (United States)

    Ping Chu, Hiu; Li, Xiao-Yan

    2005-05-05

    A submerged membrane bioreactor (MBR) with a working volume of 1.4 L and a hollow fiber microfiltration membrane was used to treat a contaminated raw water supply at a short hydraulic retention time (HRT) of approximately 1 h. Filtration flux tests were conducted regularly on the membrane to determine various fouling resistances, and confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) were employed to characterize the biofouling development and sludge cake formation on the membrane. The experimental results demonstrate that the MBR is highly effective in drinking water treatment for the removal of organic pollutants, ammonia, and UV absorbance. During the MBR operation, the fouling materials were not uniformly distributed on the entire surface of all of the membrane fibers. The membrane was covered partially by a static sludge cake that could not be removed by the shear force of aeration, and partially by a thin sludge film that was frequently washed away by aeration turbulence. The filtration resistance coefficients were 308.4 x 10(11) m(-1) on average for the sludge cake, 32.5 x 10(11) m(-1) on average for the dynamic sludge film, and increased from 10.5 x 10(11) to 59.7 x 10(11) m(-1) for the membrane pore fouling after 10 weeks of MBR operation at a filtration flux of 0.5 m3/m2 x d. Polysaccharides and other biopolymers were found to accumulate on the membrane, and hence decreased membrane permeability. More important, the adsorption of biopolymers on the membrane modified its surface property and led to easier biomass attachment and tighter sludge cake deposition, which resulted in a progressive sludge cake growth and serious membrane fouling. The sludge cake coverage on the membrane can be minimized by the separation, with adequate space, of the membrane filters, to which sufficient aeration turbulence can then be applied.

  19. LPS Remodeling Triggers Formation of Outer Membrane Vesicles in Salmonella

    Science.gov (United States)

    Elhenawy, Wael; Bording-Jorgensen, Michael; Valguarnera, Ezequiel; Haurat, M. Florencia; Wine, Eytan

    2016-01-01

    ABSTRACT Outer membrane vesicles (OMV) are proposed to mediate multiple functions during pathogenesis and symbiosis. However, the mechanisms responsible for OMV formation remain poorly understood. It has been shown in eukaryotic membranes that lipids with an inverted-cone shape favor the formation of positive membrane curvatures. Based on these studies, we formulated the hypothesis that lipid A deacylation might impose shape modifications that result in the curvature of the outer membrane (OM) and subsequent OMV formation. We tested the effect of lipid A remodeling on OMV biogenesis employing Salmonella enterica serovar Typhimurium as a model organism. Expression of the lipid A deacylase PagL resulted in increased vesiculation, without inducing an envelope stress response. Mass spectrometry analysis revealed profound differences in the patterns of lipid A in OM and OMV, with accumulation of deacylated lipid A forms exclusively in OMV. OMV biogenesis by intracellular bacteria upon macrophage infection was drastically reduced in a pagL mutant strain. We propose a novel mechanism for OMV biogenesis requiring lipid A deacylation in the context of a multifactorial process that involves the orchestrated remodeling of the outer membrane. PMID:27406567

  20. LPS Remodeling Triggers Formation of Outer Membrane Vesicles in Salmonella

    Directory of Open Access Journals (Sweden)

    Wael Elhenawy

    2016-07-01

    Full Text Available Outer membrane vesicles (OMV are proposed to mediate multiple functions during pathogenesis and symbiosis. However, the mechanisms responsible for OMV formation remain poorly understood. It has been shown in eukaryotic membranes that lipids with an inverted-cone shape favor the formation of positive membrane curvatures. Based on these studies, we formulated the hypothesis that lipid A deacylation might impose shape modifications that result in the curvature of the outer membrane (OM and subsequent OMV formation. We tested the effect of lipid A remodeling on OMV biogenesis employing Salmonella enterica serovar Typhimurium as a model organism. Expression of the lipid A deacylase PagL resulted in increased vesiculation, without inducing an envelope stress response. Mass spectrometry analysis revealed profound differences in the patterns of lipid A in OM and OMV, with accumulation of deacylated lipid A forms exclusively in OMV. OMV biogenesis by intracellular bacteria upon macrophage infection was drastically reduced in a pagL mutant strain. We propose a novel mechanism for OMV biogenesis requiring lipid A deacylation in the context of a multifactorial process that involves the orchestrated remodeling of the outer membrane.

  1. Mechanical properties of hyaline and repair cartilage studied by nanoindentation.

    Science.gov (United States)

    Franke, O; Durst, K; Maier, V; Göken, M; Birkholz, T; Schneider, H; Hennig, F; Gelse, K

    2007-11-01

    Articular cartilage is a highly organized tissue that is well adapted to the functional demands in joints but difficult to replicate via tissue engineering or regeneration. Its viscoelastic properties allow cartilage to adapt to both slow and rapid mechanical loading. Several cartilage repair strategies that aim to restore tissue and protect it from further degeneration have been introduced. The key to their success is the quality of the newly formed tissue. In this study, periosteal cells loaded on a scaffold were used to repair large partial-thickness cartilage defects in the knee joint of miniature pigs. The repair cartilage was analyzed 26 weeks after surgery and compared both morphologically and mechanically with healthy hyaline cartilage. Contact stiffness, reduced modulus and hardness as key mechanical properties were examined in vitro by nanoindentation in phosphate-buffered saline at room temperature. In addition, the influence of tissue fixation with paraformaldehyde on the biomechanical properties was investigated. Although the repair process resulted in the formation of a stable fibrocartilaginous tissue, its contact stiffness was lower than that of hyaline cartilage by a factor of 10. Fixation with paraformaldehyde significantly increased the stiffness of cartilaginous tissue by one order of magnitude, and therefore, should not be used when studying biomechanical properties of cartilage. Our study suggests a sensitive method for measuring the contact stiffness of articular cartilage and demonstrates the importance of mechanical analysis for proper evaluation of the success of cartilage repair strategies.

  2. A mechanism of raft formation on both plasma membrane layers

    Science.gov (United States)

    Sornbundit, Kan; Modchang, Charin; Triampo, Wannapong; Triampo, Darapond; Nuttavut, Narin

    2013-10-01

    A double-layered membrane model is proposed to explain raft formation and induction on extracellular (outer) and cytoplasmic (inner) leaflets of plasma membranes in a situation where only the outer layer has a tendency to phase-separate. In the model, lipid exchange with the surrounding medium is allowed on both layers, but lipid exchange between layers is not allowed. Simulations display domain stabilization on both layers. The effect of the lipid recycling frequencies on stationary domain sizes is also investigated. It is found that stationary domain sizes decrease when lipid recycling frequencies are stronger. Linear stability analysis is used to verify the results.

  3. Graphene-Induced Pore Formation on Cell Membranes

    Science.gov (United States)

    Duan, Guangxin; Zhang, Yuanzhao; Luan, Binquan; Weber, Jeffrey K.; Zhou, Royce W.; Yang, Zaixing; Zhao, Lin; Xu, Jiaying; Luo, Judong; Zhou, Ruhong

    2017-01-01

    Examining interactions between nanomaterials and cell membranes can expose underlying mechanisms of nanomaterial cytotoxicity and guide the design of safer nanomedical technologies. Recently, graphene has been shown to exhibit potential toxicity to cells; however, the molecular processes driving its lethal properties have yet to be fully characterized. We here demonstrate that graphene nanosheets (both pristine and oxidized) can produce holes (pores) in the membranes of A549 and Raw264.7 cells, substantially reducing cell viability. Electron micrographs offer clear evidence of pores created on cell membranes. Our molecular dynamics simulations reveal that multiple graphene nanosheets can cooperate to extract large numbers of phospholipids from the membrane bilayer. Strong dispersion interactions between graphene and lipid-tail carbons result in greatly depleted lipid density within confined regions of the membrane, ultimately leading to the formation of water-permeable pores. This cooperative lipid extraction mechanism for membrane perforation represents another distinct process that contributes to the molecular basis of graphene cytotoxicity. PMID:28218295

  4. Structure formation of surfactant membranes under shear flow

    Science.gov (United States)

    Shiba, Hayato; Noguchi, Hiroshi; Gompper, Gerhard

    2013-07-01

    Shear-flow-induced structure formation in surfactant-water mixtures is investigated numerically using a meshless-membrane model in combination with a particle-based hydrodynamics simulation approach for the solvent. At low shear rates, uni-lamellar vesicles and planar lamellae structures are formed at small and large membrane volume fractions, respectively. At high shear rates, lamellar states exhibit an undulation instability, leading to rolled or cylindrical membrane shapes oriented in the flow direction. The spatial symmetry and structure factor of this rolled state agree with those of intermediate states during lamellar-to-onion transition measured by time-resolved scatting experiments. Structural evolution in time exhibits a moderate dependence on the initial condition.

  5. Pattern Formation by Electrostatic Self-Organization of Membrane Proteins

    Science.gov (United States)

    Boedec, G.; Jaeger, M.; Homble, F.; Leonetti, M.

    2012-07-01

    The electric activity of biological cells and organs such as heart for example is at the origin of various phenomena of pattern formation. The electric membrane potential appears as the order parameter to characterize these spatiotemporal dynamics. A kind of patterns is characterized by a stationary spatial modulation of membrane potential along the cell, breaking a symmetry of the system. They are associated to transcellular currents. A mechanism proposed in literature is based on the coupling of the electric current produced by membrane proteins and their electrophoretic mobilities. Beyond its classical linear stability analysis, the numerical and theoretical analysis of this model offers a variety of spatiotemporal dynamics. Firstly, the background in the modelization of electric phenomena is recalled. Secondly, the analysis is focused on two nonlinear dynamics.

  6. Solid-Supported Lipid Membranes: Formation, Stability and Applications

    Science.gov (United States)

    Goh, Haw Zan

    This thesis presents a comprehensive investigation of the formation of supported lipid membranes with vesicle hemifusion, their stability under detergents and organic solvents and their applications in molecular biology. In Chapter 3, we describe how isolated patches of DOPC bilayers supported on glass surfaces are dissolved by various detergents (decyl maltoside, dodecyl maltoside, CHAPS, CTAB, SDS, TritonX-100 and Tween20) at their CMC, as investigated by fluorescence video microscopy. In general, detergents partition into distal leaflets of bilayers and lead to the expansion of the bilayers through a rolling motion of the distal over the proximal leaflets, in agreement with the first stage of the established 3-stage model of lipid vesicle solubilization by detergents. Subsequently, we study the partitioning of organic solvents (methanol, ethanol, isopropanol, propanol, acetone and chloroform) into isolated bilayer patches on glass in Chapter 4 with fluorescence microscopy. The area expansion of bilayers due to the partitioning of organic solvents is measured. From the titration of organic solvents, we measured the rate of area expansion as a function of the volume fraction of organic solvents, which is proposed to be a measure of strength of interactions between solvents and membranes. From the same experiments, we also measure the maximum expansion of bilayers (or the maximum binding stoichiometry between organic solvents and lipids) before structural breakdown, which depends on the depth of penetration of solvents to the membranes. In Chapter 5, we investigate the formation of sparsely-tethered bilayer lipid membranes (stBLMs) with vesicle hemifusion. In vesicle hemifusion, lipid vesicles in contact with a hydrophobic alkyl-terminated self-assembled monolayer (SAM) deposit a lipid monolayer to the SAM surface, thus completing the bilayer. Electrical Impedance Spectroscopy and Neutron Reflectivity are used to probe the integrity of stBLMs in terms of their

  7. Membrane Pore Formation by Amyloid beta (25-35) Peptide

    Science.gov (United States)

    Kandel, Nabin; Tatulian, Suren

    Amyloid (A β) peptide contributes to Alzheimer's disease by a yet unidentified mechanism. One of the possible mechanisms of A β toxicity is formation of pores in cellular membranes. We have characterized the formation of pores in phospholipid membranes by the Aβ25 - 35 peptide (GSNKGAIIGLM) using fluorescence, Fourier transform infrared spectroscopy (FTIR) and circular dichroism (CD) techniques. CD and FTIR identified formation of β-sheet structure upon incubation of the peptide in aqueous buffer for 2 hours. Unilamellar vesicles composed of a zwitterionic lipid, 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC), and 70 % POPC plus 30 % of an acidic lipid, 1-palmitoyl-2-oleoyl-phosphatidylglycerol (POPG), are made in 30 mM CaCl2. Quin-2, a fluorophore that displays increased fluorescence upon Ca2+ binding, is added to the vesicles externally. Peptide addition results in increased Quin-2 fluorescence, which is interpreted by binding of the peptide to the vesicles, pore formation, and Ca2+ leakage. The positive and negative control measurements involve addition of a detergent, Triton X-100, which causes vesicle rupture and release of total calcium, and blank buffer, respectively.

  8. Castleman′s disease: Hyaline vascular type

    Directory of Open Access Journals (Sweden)

    Srikanth Shastry

    2014-01-01

    Full Text Available Castleman′s disease is a rare disease of lymph node with two identified forms, the hyaline vascular type and plasma cell type. It presents as localized or systemic lymphadenopathy or even as extranodal mass and may give rise to several differential diagnoses. Castleman′s disease represents a morphologically distinct form of lymph node hyperplasia rather than a neoplasm or a hamartoma. It occurs most commonly in adults but it can also affect children. Here we present a case of Castleman′s disease in a 22 year male patient involving right cervical lymphnode.

  9. Juvenile hyaline fibromatosis: a case report.

    Science.gov (United States)

    Karaçal, Naci; Gülçelik, Nevzat; Yildiz, Kadriye; Mungan, Sevdegül; Kutlu, Necmettin

    2005-07-01

    Juvenile hyaline fibromatosis ( JHF ) is a rare autosomal recessive disease characterized by papulonodular skin lesions, gingival hyperplasia, joint contractures, and bone lesions. The skin lesions may consist of multiple large tumors, commonly on the scalp and around the neck, and small pearly, pink papules and plaques on the trunk, chin, ears, and around the nostrils. Here, we report a 2-year-old boy with characteristic stiffness of the knees and elbows and pink confluent papules on the paranasal folds, and periauricular and perianal regions. He also had hard nodules all over the scalp and around the mouth, and severe gingival hyperplasia. The lesions were totally excised and clinicopathological diagnosis was JHF.

  10. Domain Formation in Membranes Near the Onset of Instability

    Science.gov (United States)

    Fonseca, Irene; Hayrapetyan, Gurgen; Leoni, Giovanni; Zwicknagl, Barbara

    2016-10-01

    The formation of microdomains, also called rafts, in biomembranes can be attributed to the surface tension of the membrane. In order to model this phenomenon, a model involving a coupling between the local composition and the local curvature was proposed by Seul and Andelman in 1995. In addition to the familiar Cahn-Hilliard/Modica-Mortola energy, there are additional `forces' that prevent large domains of homogeneous concentration. This is taken into account by the bending energy of the membrane, which is coupled to the value of the order parameter, and reflects the notion that surface tension associated with a slightly curved membrane influences the localization of phases as the geometry of the lipids has an effect on the preferred placement on the membrane. The main result of the paper is the study of the Γ -convergence of this family of energy functionals, involving nonlocal as well as negative terms. Since the minimizers of the limiting energy have minimal interfaces, the physical interpretation is that, within a sufficiently strong interspecies surface tension and a large enough sample size, raft microdomains are not formed.

  11. Hyaline cartilage degenerates after autologous osteochondral transplantation.

    Science.gov (United States)

    Tibesku, C O; Szuwart, T; Kleffner, T O; Schlegel, P M; Jahn, U R; Van Aken, H; Fuchs, S

    2004-11-01

    Autologous osteochondral grafting is a well-established clinical procedure to treat focal cartilage defects in patients, although basic research on this topic remains sparse. The aim of the current study was to evaluate (1) histological changes of transplanted hyaline cartilage of osteochondral grafts and (2) the tissue that connects the transplanted cartilage with the adjacent cartilage in a sheep model. Both knee joints of four sheep were opened surgically and osteochondral grafts were harvested and simultaneously transplanted to the contralateral femoral condyle. The animals were sacrificed after three months and the received knee joints were evaluated histologically. Histological evaluation showed a complete ingrowth of the osseous part of the osteochondral grafts. A healing or ingrowth at the level of the cartilage could not be observed. Histological evaluation of the transplanted grafts according to Mankin revealed significantly more and more severe signs of degeneration than the adjacent cartilage, such as cloning of chondrocytes and irregularities of the articular surface. We found no connecting tissue between the transplanted and the adjacent cartilage and histological signs of degeneration of the transplanted hyaline cartilage. In the light of these findings, long-term results of autologous osteochondral grafts in human beings have to be followed critically.

  12. Autologous chondrocyte implantation: superior biologic properties of hyaline cartilage repairs.

    Science.gov (United States)

    Henderson, Ian; Lavigne, Patrick; Valenzuela, Herminio; Oakes, Barry

    2007-02-01

    Information regarding the quality of autologous chondrocyte implantation repair is needed to determine whether the current autologous chondrocyte implantation surgical technology and the subsequent biologic repair processes are capable of reliably forming durable hyaline or hyaline-like cartilage in vivo. We report and analyze the properties and qualities of autologous chondrocyte implantation repairs. We evaluated 66 autologous chondrocyte implantation repairs in 57 patients, 55 of whom had histology, indentometry, and International Cartilage Repair Society repair scoring at reoperation for mechanical symptoms or pain. International Knee Documentation Committee scores were used to address clinical outcome. Maximum stiffness, normalized stiffness, and International Cartilage Repair Society repair scoring were higher for hyaline articular cartilage repairs compared with fibrocartilage, with no difference in clinical outcome. Reoperations revealed 32 macroscopically abnormal repairs (Group B) and 23 knees with normal-looking repairs in which symptoms leading to arthroscopy were accounted for by other joint disorders (Group A). In Group A, 65% of repairs were either hyaline or hyaline-like cartilage compared with 28% in Group B. Autologous chondrocyte repairs composed of fibrocartilage showed more morphologic abnormalities and became symptomatic earlier than hyaline or hyaline-like cartilage repairs. The hyaline articular cartilage repairs had biomechanical properties comparable to surrounding cartilage and superior to those associated with fibrocartilage repairs.

  13. THE CLINICAL EFFECTS OF TWO DIFFERENT METHODS OF NASAL VENTILATION IN PRETERM INFANTS WITH HYALINE MEMBRANE DISEASE AFTER EXTUBATION%两种经鼻通气方式在肺透明膜病早产儿拔管后运用的临床效果

    Institute of Scientific and Technical Information of China (English)

    黄晓睿; 周文姬; 高薇薇; 肖苑红; 刘妙玲

    2014-01-01

    Objective To compare the clinical effects of humidified high -flow nasal cannula ( HHFNC) and nasal continu-ous positive airway pressure (nCPAP) applied in the preterm infants with hyaline membrane disease (HMD) after extubation.Meth-ods The prospectively randomized control trial was used .82 preterm infants with HMD were randomly divided into two groups re-spectively treated with HHFNC (n=42) and nCPAP (n=40) after extubation.The rate of extubation failure, reintubation, nasal trauma, and the treatment time of ventilation in 7 days after extubation were observed and compared between the two groups .Results The treatment time of ventilation , the rate of extubation failure and reintubation in 7 days after extubation between HHFNC group and nCPAP group had no statistical difference ( p>0.05 ) .But the incidence of nasal trauma of HHFNC was significantly lower than that of the nCPAP (p<0.01).Conclusion HHFNC can effectively provide respiratory support to the preterm infants with HMD as nCPAP.Compared with nCPAP, HHFNC could reduce the incidence of nasal trauma and is easier to operate .%目的:观察并比较经湿化高流量鼻导管通气治疗(Humidified High-Flow Nasal Cannula,HHFNC)与鼻塞式持续气道正压通气治疗( Nasal Continuous Positive Airway Pressure ,nCPAP)在肺透明膜病( Hyaline Membrane Disease ,HMD)早产儿气管插管拔管后运用的临床效果。方法采用前瞻性随机对照研究,将82例诊断为肺透明膜病且经气管插管接呼吸机辅助呼吸的早产儿随机分成经湿化高流量组(HHFNC组,n=42)和鼻塞气道正压组(nCPAP组,n=40),两组患儿在气管插管拔管后分别运用HHFNC和nCPAP进行通气治疗,观察并比较两组经鼻通气治疗后的7天内通气失败率和重插管率、鼻损伤发生率以及通气治疗时间。结果 HHFNC组与nCPAP组在7天内通气失败率和重插管率,以及通气治疗时间上无统计学差异(p>0.05)

  14. Comparative study on nasal continuous positive airway pressure combined with pulmonary surfactant in treatment of premature infants' Hyaline membrane disease%鼻塞式持续气道正压通气联合肺表面活性物质治疗早产儿肺透明膜病对照研究

    Institute of Scientific and Technical Information of China (English)

    刘勇; 程国平

    2011-01-01

    Objective To study the difference in curative effects of nasal continuous positive airway pressure (NCPAP) combined with pulmonary surfactant (PS) and NCPAP combined with Mucosolvan ( MU) on premature infants' Hyaline membrane disease ( HMD). Methods 90 premature infants with HMD were randomly divided into NCPAP combined with PS ( NC + PS treatment) group and MU ( NC + MU treatment) group. Curative effects, arterial blood gas, short and long term complications were compared after treatment. Results ( NC + PS) group' s total effective rate was higher than ( NC + MU) group, while the time of dyspnea remission , respirator treatment and mean hospitalization were lower than ( NC + MU) group with statistical significance (P 0.05 ) . They all increased after treatment except PaCO2, the differences in both group had statistical significance ( P < 0. 05 ). The main short term complications were pneumonia, intracranial hemorrhage and pulmonary hemorrhage; the main long term complications were cerebral palsy, hearing disorder and retinopathy of prematurity. Comprehensive situation in short and long term complications were significantly better in (NC + PS) group than (NC +MU) group (P<0.05). Conclusion NCPAP combined with PS could significantly promote curative effect on hyaline membrane disease with few short and long term complications. It is significantly better than NCPAP combined withMU.%目的 探讨鼻塞式持续气道正压通气(NCPAP)联合肺表面活性物质(PS)和NCPAP联合沐舒坦(MU)两种方法治疗早产儿肺透明膜病的疗效差异.方法 将90例肺透明膜病(HMD)早产儿随机分为NCPAP联合PS(NC+PS治疗组)和NCPAP联合MU(NC+ MU治疗组),分别进行治疗,并比较两组的疗效、动脉血气分析和近远期并发症的差异.结果 (NC+PS)组的总有效率显著高于( NC+ MU)组,而在呼吸困难缓解时间、上呼吸机时间和平均住院时间方面均小于(NC+MU)组,两组间的差异具有统计学意义(P<0.05).治

  15. Nonhomogeneous immunostaining of hyaline membranes in different manifestations of diffuse alveolar damage Imunomarcação não homogênea das membranas hialinas na sindrome da angustia respiratório do adulto pulmonar, extrapulmonar e idiopática

    Directory of Open Access Journals (Sweden)

    André Peres e Serra

    2006-01-01

    Full Text Available PURPOSE: To determine the nature of hyaline membranes in different manifestations of diffuse alveolar damage, [pulmonary and extrapulmonary acute respiratory distress syndrome], and idiopathic [acute interstitial pneumonia]. MATERIALS AND METHODS: Pulmonary specimens were obtained from 17 patients with acute respiratory distress syndrome and 9 patients with acute interstitial pneumonia. They were separated into 3 different groups: (a pulmonary diffuse alveolar damage (pDAD (n = 8, consisting only of pneumonia cases; (b extrapulmonary diffuse alveolar damage (expDAI (n = 9, consisting of sepsis and septic shock cases; and (c idiopathic diffuse alveolar damage (iDAD (n = 9, consisting of idiopathic cases (acute interstitial pneumonia. Hyaline membranes, the hallmark of the diffuse alveolar damage histological pattern, were examined using various kinds of antibodies. The antibodies used were against surfactant apoprotein-A (SP-A, cytokeratin 7 (CK7, cytokeratin 8 (CK8, alpha smooth muscle actin (a-SMA, cytokeratin AE1/AE3 (AE1/AE3, and factor VIII-related antigen (factor VIII. RESULTS: Pulmonary diffuse alveolar damage showed the largest quantity of hyaline membranes (12.65% ± 3.24%, while extrapulmonary diffuse alveolar damage (9.52% ± 3.64% and idiopathic diffuse alveolar damage (7.34% ± 2.11% showed intermediate and lower amounts, respectively, with the difference being statistically significant between pulmonary and idiopathic diffuse alveolar damage (P OBJETIVO: Determinar a natureza da membrana hialina nas diferentes manifestações do dano alveolar difuso [pulmonar e extrapulmonar síndrome do desconforto respiratório] e idiopático [pneumonia intersticial aguda]. MATERIAIS E MÉTODOS: Espécimes pulmonares foram obtidos de 17 pacientes com SDRA e 9 pacientes com pneumonia intersticial aguda e separados em três diferentes grupos: (a dano alveolar difuso pulmonar (DADp (n=8 constituído por casos de pneumonia, (b dano alveolar difuso

  16. Pulmonary hyalinizing granuloma presenting with dysphagia: a rare presentation.

    Science.gov (United States)

    Khan, Fazal; Hamid, Arsalan; Fatima, Benish; Hashmi, Shiraz; Fatimi, Saulat

    2017-01-01

    A 25-year-old man presented with a 2-month history of dysphagia and past history of pulmonary and intestinal tuberculosis. A barium swallow showed a point of constriction 42 mm above the gastroesophageal junction. Computed tomography revealed large opacities in bilateral lung fields, encroaching more on the esophagus. The lesion progressively compressed the esophagus as it moved inferiorly. A right posterolateral thoracotomy was performed for sub-anatomical resection of the mass. A biopsy revealed homogenous whirling hyalinized collagen fibers, highly suggestive of pulmonary hyalinizing granuloma, with no evidence of malignancy. Pulmonary hyalinizing granuloma should be considered in the differential diagnosis of longstanding dysphagia.

  17. Hydrostatic Pressure Promotes Domain Formation in Model Lipid Raft Membranes.

    Science.gov (United States)

    Worcester, David L; Weinrich, Michael

    2015-11-01

    Neutron diffraction measurements demonstrate that hydrostatic pressure promotes liquid-ordered (Lo) domain formation in lipid membranes prepared as both oriented multilayers and unilamellar vesicles made of a canonical ternary lipid mixture for which demixing transitions have been extensively studied. The results demonstrate an unusually large dependence of the mixing transition on hydrostatic pressure. Additionally, data at 28 °C show that the magnitude of increase in Lo caused by 10 MPa pressure is much the same as the decrease in Lo produced by twice minimum alveolar concentrations (MAC) of general anesthetics such as halothane, nitrous oxide, and xenon. Therefore, the results may provide a plausible explanation for the reversal of general anesthesia by hydrostatic pressure.

  18. Eicosapentaenoic acid reduces membrane fluidity, inhibits cholesterol domain formation, and normalizes bilayer width in atherosclerotic-like model membranes.

    Science.gov (United States)

    Mason, R Preston; Jacob, Robert F; Shrivastava, Sandeep; Sherratt, Samuel C R; Chattopadhyay, Amitabha

    2016-12-01

    Cholesterol crystalline domains characterize atherosclerotic membranes, altering vascular signaling and function. Omega-3 fatty acids reduce membrane lipid peroxidation and subsequent cholesterol domain formation. We evaluated non-peroxidation-mediated effects of eicosapentaenoic acid (EPA), other TG-lowering agents, docosahexaenoic acid (DHA), and other long-chain fatty acids on membrane fluidity, bilayer width, and cholesterol domain formation in model membranes. In membranes prepared at 1.5:1 cholesterol-to-phospholipid (C/P) mole ratio (creating pre-existing domains), EPA, glycyrrhizin, arachidonic acid, and alpha linolenic acid promoted the greatest reductions in cholesterol domains (by 65.5%, 54.9%, 46.8%, and 45.2%, respectively) compared to controls; other treatments had modest effects. EPA effects on cholesterol domain formation were dose-dependent. In membranes with 1:1 C/P (predisposing domain formation), DHA, but not EPA, dose-dependently increased membrane fluidity. DHA also induced cholesterol domain formation without affecting temperature-induced changes in-bilayer unit cell periodicity relative to controls (d-space; 57Å-55Å over 15-30°C). Together, these data suggest simultaneous formation of distinct cholesterol-rich ordered domains and cholesterol-poor disordered domains in the presence of DHA. By contrast, EPA had no effect on cholesterol domain formation and produced larger d-space values relative to controls (60Å-57Å; pmembrane bilayer width, membrane fluidity, and cholesterol crystalline domain formation; suggesting omega-3 fatty acids with differing chain length or unsaturation may differentially influence membrane lipid dynamics and structural organization as a result of distinct phospholipid/sterol interactions.

  19. Interaction of quorum signals with outer membrane lipids: insights into prokaryotic membrane vesicle formation.

    Science.gov (United States)

    Mashburn-Warren, Lauren; Howe, Jörg; Garidel, Patrick; Richter, Walter; Steiniger, Frank; Roessle, Manfred; Brandenburg, Klaus; Whiteley, Marvin

    2008-07-01

    Bacteria have evolved elaborate communication strategies to co-ordinate their group activities, a process termed quorum sensing (QS). Pseudomonas aeruginosa is an opportunistic pathogen that utilizes QS for diverse activities, including disease pathogenesis. P. aeruginosa has evolved a novel communication system in which the signal molecule 2-heptyl-3-hydroxy-4-quinolone (Pseudomonas Quinolone Signal, PQS) is trafficked between cells via membrane vesicles (MVs). Not only is PQS packaged into MVs, it is required for MV formation. Although MVs are involved in important biological processes aside from signalling, the molecular mechanism of MV formation is unknown. To provide insight into the molecular mechanism of MV formation, we examined the interaction of PQS with bacterial lipids. Here, we show that PQS interacts strongly with the acyl chains and 4'-phosphate of bacterial lipopolysaccharide (LPS). Using PQS derivatives, we demonstrate that the alkyl side-chain and third position hydroxyl of PQS are critical for these interactions. Finally, we show that PQS stimulated purified LPS to form liposome-like structures. These studies provide molecular insight into P. aeruginosa MV formation and demonstrate that quorum signals serve important non-signalling functions.

  20. Precision of hyaline cartilage thickness measurements

    Energy Technology Data Exchange (ETDEWEB)

    Jonsson, K.; Buckwalter, K.; Helvie, M.; Niklason, L.; Martel, W. (Univ. of Michigan Hospitals, Ann Arbor, MI (United States). Dept. of Radiology)

    1992-05-01

    Measurement of cartilage thickness in vivo is an important indicator of the status of a joint as the various degenerative and inflammatory arthritides directly affect the condition of the cartilage. In order to assess the precision of thickness measurements of hyaline articular cartilage, we undertook a pilot study using MR imaging, plain radiography, and ultrasonography (US). We measured the cartilage of the hip and knee joints in 10 persons (4 healthy volunteers and 6 patients). The joints in each patient were examined on two separate occasions using each modality. In the hips a swell as the knee joints, the most precise measuring method was plain film radiography. For radiographs of the knees obtained in the standing position, the coefficient of variation was 6.5%; in the hips this figure was 6.34%. US of the knees and MR imaging of the hips were the second best modalities in the measurement of cartilage thickness. In addition, MR imaging enabled the most complete visualization of the joint cartilage. (orig.).

  1. Functional Implications of Photosystem II Crystal Formation in Photosynthetic Membranes

    NARCIS (Netherlands)

    Tietz, Stefanie; Puthiyaveetil, Sujith; Enlow, Heather M; Yarbrough, Robert; Wood, Magnus; Semchonok, Dmitry A; Lowry, Troy; Li, Zhirong; Jahns, Peter; Boekema, Egbert J; Lenhert, Steven; Niyogi, Krishna K; Kirchhoff, Helmut

    2015-01-01

    The structural organization of proteins in biological membranes can affect their function. Photosynthetic thylakoid membranes in chloroplasts have the remarkable ability to change their supramolecular organization between disordered and semicrystalline states. Although the change to the semicrystall

  2. Can one generate stable hyaline cartilage from adult mesenchymal stem cells? A developmental approach.

    Science.gov (United States)

    Hellingman, Catharine A; Koevoet, Wendy; van Osch, Gerjo J V M

    2012-11-01

    Chondrogenically differentiating bone marrow-derived mesenchymal stem cells (BMSCs) display signs of chondrocyte hypertrophy, such as production of collagen type X, MMP13 and alkaline phosphatase (ALPL). For cartilage reconstructions this is undesirable, as terminally differentiated cartilage produced by BMSCs mineralizes when implanted in vivo. Terminal differentiation is not restricted to BMSCs but is also encountered in chondrogenic differentiation of adipose-derived mesenchymal stem cells (MSCs) as well as embryonic stem cells, which by definition should be able to generate all types of tissues, including stable cartilage. Therefore, we propose that the currently used culture conditions may drive the cells towards terminal differentiation. In this manuscript we aim to review the literature, supplemented by our own data to answer the question, is it possible to generate stable hyaline cartilage from adult MSCs? We demonstrate that recently published methods for inhibiting terminal differentiation (through PTHrP, MMP13 or blocking phosphorylation of Smad1/5/8) result in cartilage formation with reduction of hypertrophic markers, although this does not reach the low level of stable chondrocytes. A set of hypertrophy markers should be included in future studies to characterize the phenotype more precisely. Finally, we used what is currently known in developmental biology about the differential development of hyaline and terminally differentiated cartilage to provide thought and insights to change current culture models for creating hyaline cartilage. Inhibiting terminal differentiation may not result in stable hyaline cartilage if the right balance of signals has not been created from the start of culture onwards. Copyright © 2011 John Wiley & Sons, Ltd.

  3. Mechanism of voltage-gated channel formation in lipid membranes.

    Science.gov (United States)

    Guidelli, Rolando; Becucci, Lucia

    2016-04-01

    Although several molecular models for voltage-gated ion channels in lipid membranes have been proposed, a detailed mechanism accounting for the salient features of experimental data is lacking. A general treatment accounting for peptide dipole orientation in the electric field and their nucleation and growth kinetics with ion channel formation is provided. This is the first treatment that explains all the main features of the experimental current-voltage curves of peptides forming voltage-gated channels available in the literature. It predicts a regime of weakly voltage-dependent conductance, followed by one of strong voltage-dependent conductance at higher voltages. It also predicts values of the parameters expressing the exponential dependence of conductance upon voltage and peptide bulk concentration for both regimes, in good agreement with those reported in the literature. Most importantly, the only two adjustable parameters involved in the kinetics of nucleation and growth of ion channels can be varied over broad ranges without affecting the above predictions to a significant extent. Thus, the fitting of experimental current-voltage curves stems naturally from the treatment and depends only slightly upon the choice of the kinetic parameters.

  4. Clinical Effect of Pulmonary Surfactant Combined with Nasal Continuous Positive Airway Pressure Ventilation on Hyaline Membrane Disease in Neonates%肺表面活性物质联合鼻塞式持续气道正压通气治疗新生儿肺透明膜病的临床效果分析

    Institute of Scientific and Technical Information of China (English)

    淡云; 卫文峰

    2016-01-01

    目的:分析肺表面活性物质(PS)联合鼻塞式持续气道正压通气(NCPAP)治疗新生儿肺透明膜病的临床效果。方法选取2014年6月—2016年3月咸阳市中心医院新生儿科收治的新生儿肺透明膜病患儿80例,按照入院顺序分为对照组和试验组,每组40例。对照组患儿给予 NCPAP 治疗,试验组患儿给予 PS 联合 NCPAP 治疗。比较两组患儿治疗前后血气分析指标〔动脉血氧分压( PaO2)、PaO2/吸入氧浓度( FiO2)及动脉血二氧化碳分压(PaCO2)〕,治疗及住院情况(包括高压力持续时间、高 FiO2持续时间、NCPAP 治疗时间及住院时间),转归情况(包括治愈、再次插管机械通气、死亡、放弃治疗)及并发症情况(气胸、肺炎等)。结果时间与方法在 PaO2、PaO2/ FiO2及 PaCO2上存在交互作用(P 0.05)。试验组患儿并发症发生率低于对照组(P 0. 05). The incidence of complications of experiment group was statistically significantly lower than that of control group( P < 0. 05). Conclusion PS combined with NCPAP ventilation can effectively adjust the blood - gas analysis index,shorten the duration of NCPAP ventilation and hospital stays,reduce the ratio turned to endotracheal intubation guided respirator assisted ventilation at midway and incidence of complications of neonates with hyaline membrane disease.

  5. Effects of antimicrobial peptide revealed by simulations: translocation, pore formation, membrane corrugation and euler buckling.

    Science.gov (United States)

    Chen, Licui; Jia, Nana; Gao, Lianghui; Fang, Weihai; Golubovic, Leonardo

    2013-04-11

    We explore the effects of the peripheral and transmembrane antimicrobial peptides on the lipid bilayer membrane by using the coarse grained Dissipative Particle Dynamics simulations. We study peptide/lipid membrane complexes by considering peptides with various structure, hydrophobicity and peptide/lipid interaction strength. The role of lipid/water interaction is also discussed. We discuss a rich variety of membrane morphological changes induced by peptides, such as pore formation, membrane corrugation and Euler buckling.

  6. Organized living: formation mechanisms and functions of plasma membrane domains in yeast.

    Science.gov (United States)

    Ziółkowska, Natasza E; Christiano, Romain; Walther, Tobias C

    2012-03-01

    Plasma membrane proteins and lipids organize into lateral domains of specific composition. Domain formation is achieved by a combination of lipid-lipid and lipid-protein interactions, membrane-binding protein scaffolds and protein fences. The resulting domains function in membrane protein turnover and homeostasis, as well as in cell signaling. We review the mechanisms generating plasma membrane domains and the functional consequences of this organization, focusing on recent findings from research on the yeast model system.

  7. In vivo cluster formation of nisin and lipid II is correlated with membrane depolarization.

    Science.gov (United States)

    Tol, Menno B; Morales Angeles, Danae; Scheffers, Dirk-Jan

    2015-01-01

    Nisin and related lantibiotics kill bacteria by pore formation or by sequestering lipid II. Some lantibiotics sequester lipid II into clusters, which were suggested to kill cells through delocalized peptidoglycan synthesis. Here, we show that cluster formation is always concomitant with (i) membrane pore formation and (ii) membrane depolarization. Nisin variants that cluster lipid II kill L-form bacteria with similar efficiency, suggesting that delocalization of peptidoglycan synthesis is not the primary killing mechanism of these lantibiotics.

  8. Membrane tube formation by motor proteins : forces and dynamics

    NARCIS (Netherlands)

    Koster, Gerbrand

    2005-01-01

    Membrane tubes are ubiquitous within cells. They have a diameter of approximately 50 nanometers, and are formed when a sufficiently large localized force is exerted on a membrane. Important generators of this force are the motor proteins that can move along cytoskeletal filaments. We studied

  9. Ice Formation in Model Biological Membranes in the Presence of Cryoprotectors

    CERN Document Server

    Kiselev, M A; Kisselev, A M; Ollivon, M

    2000-01-01

    Ice formation in model biological membranes is studied by SAXS and WAXS in the presence of cryoprotectors: dimethyl sulfoxide and glycerol. Three types of phospholipid membranes: DPPC, DMPC, DSPC are chosen for the investigation as well-studied model biological membranes. A special cryostat is used for sample cooling from 14.1C to -55.4C. The ice formation is only detected by WAXS in binary phospholipid/water and ternary phospholipid/cryoprotector/water systems in the condition of excess solvent. Ice formation in a binary phospholipid/water system creates an abrupt decrease of the membrane repeat distance by delta-d, so-called ice-induced dehydration of intermembrane space. The value of delta-d decreases as the cryoprotector concentration increases. The formation of ice does not influence the membrane structure (delta-d = 0) for cryoprotector mole fractions higher than 0.05.

  10. Axon-glia interaction and membrane traffic in myelin formation

    OpenAIRE

    2014-01-01

    In vertebrate nervous systems myelination of neuronal axons has evolved to increase conduction velocity of electrical impulses with minimal space and energy requirements. Myelin is formed by specialized glial cells which ensheath axons with a lipid-rich insulating membrane. Myelination is a multi-step process initiated by axon-glia recognition triggering glial polarization followed by targeted myelin membrane expansion and compaction. Thereby, a myelin sheath of complex subdomain structure is...

  11. Mechanism of membranous tunnelling nanotube formation in viral genome delivery.

    Directory of Open Access Journals (Sweden)

    Bibiana Peralta

    2013-09-01

    Full Text Available In internal membrane-containing viruses, a lipid vesicle enclosed by the icosahedral capsid protects the genome. It has been postulated that this internal membrane is the genome delivery device of the virus. Viruses built with this architectural principle infect hosts in all three domains of cellular life. Here, using a combination of electron microscopy techniques, we investigate bacteriophage PRD1, the best understood model for such viruses, to unveil the mechanism behind the genome translocation across the cell envelope. To deliver its double-stranded DNA, the icosahedral protein-rich virus membrane transforms into a tubular structure protruding from one of the 12 vertices of the capsid. We suggest that this viral nanotube exits from the same vertex used for DNA packaging, which is biochemically distinct from the other 11. The tube crosses the capsid through an aperture corresponding to the loss of the peripentonal P3 major capsid protein trimers, penton protein P31 and membrane protein P16. The remodeling of the internal viral membrane is nucleated by changes in osmolarity and loss of capsid-membrane interactions as consequence of the de-capping of the vertices. This engages the polymerization of the tail tube, which is structured by membrane-associated proteins. We have observed that the proteo-lipidic tube in vivo can pierce the gram-negative bacterial cell envelope allowing the viral genome to be shuttled to the host cell. The internal diameter of the tube allows one double-stranded DNA chain to be translocated. We conclude that the assembly principles of the viral tunneling nanotube take advantage of proteo-lipid interactions that confer to the tail tube elastic, mechanical and functional properties employed also in other protein-membrane systems.

  12. Nanoviscosity Measurements Revealing Domain Formation in Biomimetic Membranes.

    Science.gov (United States)

    Hasan, Imad Younus; Mechler, Adam

    2017-02-07

    Partitioning of lipid molecules in biomimetic membranes is a model system for the study of naturally occurring domains, such as rafts, in biological membranes. The existence of nanometer scale membrane domains in binary lipid mixtures has been shown with microscopy methods; however, the nature of these domains has not been established unequivocally. A common notion is to ascribe domain separation to thermodynamic phase equilibria. However, characterizing thermodynamic phases of single bilayer membranes has not been possible due to their extreme dimensions: the size of the domains falls to the order of tens to hundreds of nanometers whereas the membrane thickness is only a few nanometers. Here, we present direct measurements of phase transitions in single bilayers of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC)/1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) phospholipid mixtures using quartz crystal microbalance-based nanoviscosity measurements. Coexisting thermodynamic phases have been successfully identified, and a phase diagram was constructed for the single bilayer binary lipid system. It was demonstrated that domain separation only takes place in planar membranes, and thus, it is absent in liposomes and not detectable in calorimetric measurements on liposome suspensions. On the basis of energetic analysis, the main transition was identified as the breaking of van der Waals interactions between the acyl chains.

  13. Counterion-mediated pattern formation in membranes containing anionic lipids.

    Science.gov (United States)

    Slochower, David R; Wang, Yu-Hsiu; Tourdot, Richard W; Radhakrishnan, Ravi; Janmey, Paul A

    2014-06-01

    Most lipid components of cell membranes are either neutral, like cholesterol, or zwitterionic, like phosphatidylcholine and sphingomyelin. Very few lipids, such as sphingosine, are cationic at physiological pH. These generally interact only transiently with the lipid bilayer, and their synthetic analogs are often designed to destabilize the membrane for drug or DNA delivery. However, anionic lipids are common in both eukaryotic and prokaryotic cell membranes. The net charge per anionic phospholipid ranges from -1 for the most abundant anionic lipids such as phosphatidylserine, to near -7 for phosphatidylinositol 3,4,5 trisphosphate, although the effective charge depends on many environmental factors. Anionic phospholipids and other negatively charged lipids such as lipopolysaccharides are not randomly distributed in the lipid bilayer, but are highly restricted to specific leaflets of the bilayer and to regions near transmembrane proteins or other organized structures within the plane of the membrane. This review highlights some recent evidence that counterions, in the form of monovalent or divalent metal ions, polyamines, or cationic protein domains, have a large influence on the lateral distribution of anionic lipids within the membrane, and that lateral demixing of anionic lipids has effects on membrane curvature and protein function that are important for biological control. Copyright © 2014. Published by Elsevier B.V.

  14. Hyaline fibromatosis of Hoffa's fat pad in a patient with a mild type of hyaline fibromatosis syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Raak, Sjoerd M. van [Albert Schweitzer Hospital, Department of Radiology, Dordrecht (Netherlands); Meuffels, Duncan E. [Erasmus MC - University Medical Center, Department of Orthopaedic Surgery, Rotterdam (Netherlands); Leenders, Geert J.L.H. van [Erasmus MC - University Medical Center, Department of Pathology, Rotterdam (Netherlands); Oei, Edwin H.G. [Erasmus MC - University Medical Center, Department of Radiology, Rotterdam (Netherlands)

    2014-04-15

    Hyaline fibromatosis syndrome (HFS) is a rare, homozygous, autosomal recessive disease, characterized by deposition of hyaline material in skin and other organs, resulting in esthetic problems, disability, and potential life-threatening complications. Most patients become clinically apparent in the first few years of life, and the disorder typically progresses with the appearance of new lesions. We describe a rare case of a 20-year-old patient with juvenile-onset mild HFS who presented with a history of progressive anterior knee pain. Detailed magnetic resonance (MR) imaging findings with histopathological correlation are presented of hyaline fibromatosis of Hoffa's fat pad, including differential diagnosis. The diagnosis of HFS is generally made on basis of clinical and histopathological findings. Imaging findings, however, may contribute to the correct diagnosis in patients who present with a less typical clinical course of HFS. (orig.)

  15. The More the Tubular: Dynamic Bundling of Actin Filaments for Membrane Tube Formation.

    Directory of Open Access Journals (Sweden)

    Julian Weichsel

    2016-07-01

    Full Text Available Tubular protrusions are a common feature of living cells, arising from polymerization of stiff protein filaments against a comparably soft membrane. Although this process involves many accessory proteins in cells, in vitro experiments indicate that similar tube-like structures can emerge without them, through spontaneous bundling of filaments mediated by the membrane. Using theory and simulation of physical models, we have elaborated how nonequilibrium fluctuations in growth kinetics and membrane shape can yield such protrusions. Enabled by a new grand canonical Monte Carlo method for membrane simulation, our work reveals a cascade of dynamical transitions from individually polymerizing filaments to highly cooperatively growing bundles as a dynamical bottleneck to tube formation. Filament network organization as well as adhesion points to the membrane, which bias filament bending and constrain membrane height fluctuations, screen the effective attractive interactions between filaments, significantly delaying bundling and tube formation.

  16. Simulations of Pore Formation in Lipid Membranes: Reaction Coordinates, Convergence, Hysteresis, and Finite-Size Effects.

    Science.gov (United States)

    Awasthi, Neha; Hub, Jochen S

    2016-07-12

    Transmembrane pores play an important role in various biophysical processes such as membrane permeation, membrane fusion, and antimicrobial peptide activity. In principal, all-atom molecular dynamics (MD) simulations provide an accurate model of pore formation in lipid membranes. However, the free energy landscape of transmembrane pore formation remains poorly understood, partly because potential of mean force (PMF) calculations of pore formation strongly depend on the choice of the reaction coordinate. In this study, we used umbrella sampling to compute PMFs for pore formation using three different reaction coordinates, namely, (i) a coordinate that steers the lipids in the lateral direction away from the pore center, (ii) the distance of a single lipid phosphate group from the membrane center, and (iii) the average water density inside a membrane-spanning cylinder. Our results show that while the three reaction coordinates efficiently form pores in membranes, they suffer from strong hysteresis between pore-opening and pore-closing simulations, suggesting that they do not restrain the systems close to the transition state for pore formation. The two reaction coordinates that act via restraining the lipids lead to more pronounced hysteresis compared with the coordinate acting on the water molecules. By comparing PMFs computed from membranes with different numbers of lipids, we observed significant artifacts from the periodic boundary conditions in small simulation systems. Further analysis suggests that the formation and disruption of a continuous hydrogen-bonding network across the membrane corresponds to the transition state for pore formation. Our study provides molecular insights into the critical steps of transmembrane pore formation, and it may guide the development of efficient reaction coordinates for pore formation.

  17. The formation of endosymbiotic membrane compartments: membrane identity markers and the regulation of vesicle trafficking

    NARCIS (Netherlands)

    Ivanov, S.

    2012-01-01

    In symbiosis of plants and arbuscular mycorrhizal fungi as well as in rhizobium-legume symbiosis the microbes are hosted intracellularly, inside specialized membrane compartments of the host. These membrane compartments are morphologically different but similar in function, since they control the ex

  18. 气管内滴注肺表面活性物质治疗新生儿肺透明膜病效果分析%Analysis of Efficacy of Hyaline Membrane Disease of Newborn Treated with Pulmonary Surfactant by Endotracheal Instillation

    Institute of Scientific and Technical Information of China (English)

    陈燕霞; 罗素云; 廖艳霞

    2012-01-01

    Objective To study the efficacy and safety of pulmonary surfactant used in hyaline membrane disease(HMD)of newborn treatment.Methods 67 cases of HMD children were treated.And pulmonary surfactant was used by intratracheal instillation.Clinical manifestation,blood gas analysis,X-ray chest film and complication before and after treatment were observed and recorded.Results 65 cases of children were recovered and discharged(97.01%),while 2 cases were dead.The PO2 increased significantly after the surfactant was given(P<0.05),while the PCO2 decreased significantly(P<0.05),and situation of skin cyanosis was relieved.X-ray chest films in 24 hours showed that 62 cases were improved(92.54%),while 4 cases were not obvious(5.97%),and there was hemorrhage image in the last 1 caes(1.49%).There were 5 cases of complication,involving 3 cases of pneumonia,1 case of intracranial hemorrhage and 1 case of pulmonary hemorrhage.Conclusion Clinical symptoms could be impurved rapidly,pulmonary oxygenation could be ameliorated,the need of mechanical ventilation could be lower and the rate of incidence of complication and death could be reduced effectively by using pulmonary surfactant early.%目的 探讨气管内滴注肺表面活性物质治疗新生儿肺透明膜病的效果及安全性.方法 选择新生儿肺透明膜病患儿67例,采用气管内注入单剂肺表面活性物质治疗,观察患儿治疗前后的临床表现、血气、X线胸片以及并发症情况.结果 痊愈出院65例(97.01%),死亡2例;给药后患儿氧分压(PO2)和动脉血氧饱和度(SaO2)明显升高(P<0.05),二氧化碳分压(PCO2)明显下降(P<0.05),皮肤发绀、青紫状况缓解.24 h内复查胸片示肺野透明情况显著改善62例(92.54%),无明显改善4例(5.97%),有合并肺出血影像1例(1.49%).共发生并发症5例,其中肺炎3例,颅内出血1例,肺出血1例.结论 早期应用肺表面活性物质能快速改善肺透明膜病患儿的临床症状,改

  19. Clinical nursing of HFOV plus CMV on premature newborns with hyaline membrane disease%高频振荡通气加常频通气治疗早产儿肺透明膜病的临床和护理研究

    Institute of Scientific and Technical Information of China (English)

    叶蕾; 杨小红; 孙小娟

    2012-01-01

    Objective To study the effect and nursing strategies of high frequency oscillatory ventilation (HFOV) plus conventional mandatory ventilation (CMV)on treating critical hyaline membrane disease(HMD). Methods A total of 18 infants with critical HMD in the NICU from January 2009 to December 2010 were enrolled and divided into treatment group(HFOV plus CMV) and control group(CMV). Clinical efficacy, ventilator parameters, blood gas analysis and complications (pneumothorax, intracranial hemorrhage) were compared between the two groups. Nursing strategies were summarized accordingly. Results After 24 h treatment, PO2, MAP, OI and outcome of the treatment group were better than those of the control group (P<0. 05). Compared with the control group, the incidence of pneumothorax in the treatment group was significantly low-er(P<0.05). But no statistical significance was found in incidence of intracranial hemorrhage between the two groups(P<0. 05). Conclusion HFOV plus CMV can improve lung oxygenation and clinical outcome, and reduce the incidence rate of pneumothorax without increasing the risk of intracranial hemorrhage. The effect is superior to conventional mandatory ventilation. During the treatment process, nursing cooperation related to high - quality mechanical ventilation is paramount to an successful treatment.%目的 研究高频振荡通气加常频通气治疗早产儿肺透明膜病的临床疗效和护理特点.方法 以2009年1月~2010年12月在本院新生儿重症监护室(NICU)住院采用机械通气治疗的18例早产儿肺透明膜病(HMD)患儿为研究对象,随机分为研究组10例和对照组8例,研究组通气模式为高频振荡通气加常频通气,对照组采用为常频通气模式,比较两组患儿上机后临床疗效、呼吸机参数、氧合指标以及气胸、颅内出血等并发症的发生率,同时总结高频振荡通气加常频通气的护理特点和体会.结果 研究组上机24 h后吸氧浓度(FiO2)、平均气道

  20. Effect of additive on the formation of polyacrylonitrile membrane

    Institute of Scientific and Technical Information of China (English)

    YANG Sen; LIU Zhong-zhou

    2004-01-01

    The effect of additives CaCl2 and CaCl2/H2O on the properties of polyacrylonitrile(PAN) ultrafiltration(UF)membranes prepared by phase inversion process was studied. The dissolving capacity of the casting solution forCaCl2 was enhanced by the addition of H2O. The membranes are characterized in terms of the pure water flux andmolecular weight cut-off( MWCO). The addition of CaCl2 or CaCl2/H2O to the casting solution increases the resultingmembrane permeability.

  1. Natural organic matter interactions with polyamide and polysulfone membranes: Formation of conditioning film

    KAUST Repository

    Gutierrez, Leonardo

    2015-03-31

    A conditioning film changes the physicochemical properties of the membrane surface and strongly affects subsequent fouling behavior. Results from this Atomic Force Microscopy study indicate that Natural Organic Matter (NOM) characteristics, membrane surface properties, and solution chemistry are fundamental during conditioning film formation. Repulsive forces were observed between HUM (humic-NOM) and Polyamide (PA) or Polysulfone (PS) membranes during approach in Na+ and Ca2+ solutions. However, repulsive and attractive forces were randomly recorded during BIOP (biopolymer-NOM) approach to both membranes, possibly caused by low electrostatic repulsion, hydrogen bonding, and presence of chemically/physically heterogeneous regions on membrane surfaces. During retracting, Ca2+ ions increased HUM adhesion to PA and PS membrane, indicating cation bridging/complexation as dominant interacting mechanism for this isolate. BIOP adsorption on PS and PA membrane was stronger than HUM under similar solution conditions, where hydrogen bonding would play an important role. Additionally, irrespective of solution conditions, higher adhesion energy was recorded on PS than on PA membrane for both NOM isolates, indicating membrane hydrophobicity as an important interacting factor. Results from this research will advance our understanding of conditioning film formation for NOM isolates and membranes of different physicochemical characteristics.

  2. Deciphering How Pore Formation Causes Strain-Induced Membrane Lysis of Lipid Vesicles.

    Science.gov (United States)

    Jackman, Joshua A; Goh, Haw Zan; Zhdanov, Vladimir P; Knoll, Wolfgang; Cho, Nam-Joon

    2016-02-01

    Pore formation by membrane-active antimicrobial peptides is a classic strategy of pathogen inactivation through disruption of membrane biochemical gradients. It remains unknown why some membrane-active peptides also inhibit enveloped viruses, which do not depend on biochemical gradients. Here, we employ a label-free biosensing approach based on simultaneous quartz crystal microbalance-dissipation and ellipsometry measurements in order to investigate how a pore-forming, virucidal peptide destabilizes lipid vesicles in a surface-based experimental configuration. A key advantage of the approach is that it enables direct kinetic measurement of the surface-bound peptide-to-lipid (P:L) ratio. Comprehensive experiments involving different bulk peptide concentrations and biologically relevant membrane compositions support a unified model that membrane lysis occurs at or above a critical P:L ratio, which is at least several-fold greater than the value corresponding to the onset of pore formation. That is consistent with peptide-induced pores causing additional membrane strain that leads to lysis of highly curved membranes. Collectively, the work presents a new model that describes how peptide-induced pores may destabilize lipid membranes through a membrane strain-related lytic process, and this knowledge has important implications for the design and application of membrane-active peptides.

  3. Hydrogels as a Replacement Material for Damaged Articular Hyaline Cartilage

    Directory of Open Access Journals (Sweden)

    Charlotte M. Beddoes

    2016-06-01

    Full Text Available Hyaline cartilage is a strong durable material that lubricates joint movement. Due to its avascular structure, cartilage has a poor self-healing ability, thus, a challenge in joint recovery. When severely damaged, cartilage may need to be replaced. However, currently we are unable to replicate the hyaline cartilage, and as such, alternative materials with considerably different properties are used. This results in undesirable side effects, including inadequate lubrication, wear debris, wear of the opposing articular cartilage, and weakening of the surrounding tissue. With the number of surgeries for cartilage repair increasing, a need for materials that can better mimic cartilage, and support the surrounding material in its typical function, is becoming evident. Here, we present a brief overview of the structure and properties of the hyaline cartilage and the current methods for cartilage repair. We then highlight some of the alternative materials under development as potential methods of repair; this is followed by an overview of the development of tough hydrogels. In particular, double network (DN hydrogels are a promising replacement material, with continually improving physical properties. These hydrogels are coming closer to replicating the strength and toughness of the hyaline cartilage, while offering excellent lubrication. We conclude by highlighting several different methods of integrating replacement materials with the native joint to ensure stability and optimal behaviour.

  4. Functional Implications of Photosystem II Crystal Formation in Photosynthetic Membranes*

    Science.gov (United States)

    Tietz, Stefanie; Puthiyaveetil, Sujith; Enlow, Heather M.; Yarbrough, Robert; Wood, Magnus; Semchonok, Dmitry A.; Lowry, Troy; Li, Zhirong; Jahns, Peter; Boekema, Egbert J.; Lenhert, Steven; Niyogi, Krishna K.; Kirchhoff, Helmut

    2015-01-01

    The structural organization of proteins in biological membranes can affect their function. Photosynthetic thylakoid membranes in chloroplasts have the remarkable ability to change their supramolecular organization between disordered and semicrystalline states. Although the change to the semicrystalline state is known to be triggered by abiotic factors, the functional significance of this protein organization has not yet been understood. Taking advantage of an Arabidopsis thaliana fatty acid desaturase mutant (fad5) that constitutively forms semicrystalline arrays, we systematically test the functional implications of protein crystals in photosynthetic membranes. Here, we show that the change into an ordered state facilitates molecular diffusion of photosynthetic components in crowded thylakoid membranes. The increased mobility of small lipophilic molecules like plastoquinone and xanthophylls has implications for diffusion-dependent electron transport and photoprotective energy-dependent quenching. The mobility of the large photosystem II supercomplexes, however, is impaired, leading to retarded repair of damaged proteins. Our results demonstrate that supramolecular changes into more ordered states have differing impacts on photosynthesis that favor either diffusion-dependent electron transport and photoprotection or protein repair processes, thus fine-tuning the photosynthetic energy conversion. PMID:25897076

  5. Functional Implications of Photosystem II Crystal Formation in Photosynthetic Membranes.

    Science.gov (United States)

    Tietz, Stefanie; Puthiyaveetil, Sujith; Enlow, Heather M; Yarbrough, Robert; Wood, Magnus; Semchonok, Dmitry A; Lowry, Troy; Li, Zhirong; Jahns, Peter; Boekema, Egbert J; Lenhert, Steven; Niyogi, Krishna K; Kirchhoff, Helmut

    2015-05-29

    The structural organization of proteins in biological membranes can affect their function. Photosynthetic thylakoid membranes in chloroplasts have the remarkable ability to change their supramolecular organization between disordered and semicrystalline states. Although the change to the semicrystalline state is known to be triggered by abiotic factors, the functional significance of this protein organization has not yet been understood. Taking advantage of an Arabidopsis thaliana fatty acid desaturase mutant (fad5) that constitutively forms semicrystalline arrays, we systematically test the functional implications of protein crystals in photosynthetic membranes. Here, we show that the change into an ordered state facilitates molecular diffusion of photosynthetic components in crowded thylakoid membranes. The increased mobility of small lipophilic molecules like plastoquinone and xanthophylls has implications for diffusion-dependent electron transport and photoprotective energy-dependent quenching. The mobility of the large photosystem II supercomplexes, however, is impaired, leading to retarded repair of damaged proteins. Our results demonstrate that supramolecular changes into more ordered states have differing impacts on photosynthesis that favor either diffusion-dependent electron transport and photoprotection or protein repair processes, thus fine-tuning the photosynthetic energy conversion.

  6. Theoretical Model for the Formation of Caveolae and Similar Membrane Invaginations

    Science.gov (United States)

    Sens, Pierre; Turner, Matthew S.

    2004-01-01

    We study a physical model for the formation of bud-like invaginations on fluid lipid membranes under tension, and apply this model to caveolae formation. We demonstrate that budding can be driven by membrane-bound proteins, provided that they exert asymmetric forces on the membrane that give rise to bending moments. In particular, caveolae formation does not necessarily require forces to be applied by the cytoskeleton. Our theoretical model is able to explain several features observed experimentally in caveolae, where proteins in the caveolin family are known to play a crucial role in the formation of caveolae buds. These include 1), the formation of caveolae buds with sizes in the 100-nm range and 2), that certain N- and C-termini deletion mutants result in vesicles that are an order-of-magnitude larger. Finally, we discuss the possible origin of the morphological striations that are observed on the surfaces of the caveolae. PMID:15041647

  7. Outer membrane lipoprotein VacJ is required for the membrane integrity, serum resistance and biofilm formation of Actinobacillus pleuropneumoniae.

    Science.gov (United States)

    Xie, Fang; Li, Gang; Zhang, Wanjiang; Zhang, Yanhe; Zhou, Long; Liu, Shuanghong; Liu, Siguo; Wang, Chunlai

    2016-02-01

    The outer membrane proteins of Actinobacillus pleuropneumoniae are mediators of infection, acting as targets for the host's defense system. The outer membrane lipoprotein VacJ is involved in serum resistance and intercellular spreading in several pathogenic bacteria. To investigate the role of VacJ in the pathogenicity of Actinobacillus pleuropneumoniae, the vacJ gene-deletion mutant MD12 ΔvacJ was constructed. The increased susceptibility to KCl, SDS plus EDTA, and several antibiotics in the MD12ΔvacJ mutant suggested that the stability of the outer membrane was impaired as a result of the mutation in the vacJ gene. The increased NPN fluorescence and significant cellular morphological variation in the MD12ΔvacJ mutant further demonstrated the crucial role of the VacJ lipoprotein in maintaining the outer membrane integrity of A. pleuropneumoniae. In addition, the MD12ΔvacJ mutant exhibited decreased survival from the serum and complement killing compared to the wild-type strain. Interestingly, the MD12ΔvacJ mutant showed reduced biofilm formation compared to the wild-type strain. To our knowledge, this is the first description of the VacJ lipoprotein contributing to bacterial biofilm formation. The data presented in this study illustrate the important role of the VacJ lipoprotein in the maintenance of cellular integrity, serum resistance, and biofilm formation in A. pleuropneumoniae. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Zinc-nanosystem-structure formation using anodic-oxidized aluminum membranes

    Science.gov (United States)

    Kornyushchenko, A. S.; Perekrestov, V. I.; Natalich, V. V.; Zagaiko, I. V.

    2017-02-01

    We propose a new method for the formation of zinc nanosystems by condensation of a weakly supersaturated Zn vapor in pores of the anodic-oxidized aluminum membrane (AOA)-silicon substrate system. For this purpose, a weak Zn vapor flow is created by magnetron sputtering of Zn target in a high-purity inert gas atmosphere and maintaining a temperature of the porous AOA membrane outer surface higher than that of the substrate. This drives a directional Zn vapor flow inward membrane parallel to the pore generatrix and favors effective penetration of Zn vapor into the membrane.

  9. The development of hyaline-cell cartilage in the head of the black molly, Poecilia sphenops. Evidence for secondary cartilage in a teleost.

    Science.gov (United States)

    Benjamin, M

    1989-01-01

    The development of hyaline-cell cartilage attached to membrane (dentary, maxilla, nasal, lacrimal and cleithrum) and cartilage (basioccipital) bones has been studied in the viviparous black molly, Poecilia sphenops. Intramembranous ossification commences before the first appearance of hyaline cells. As hyaline-cell cartilage is densely cellular and as that attached to the dentary, maxilla and cleithrum develops from the periosteum of these membrane bones, it must be regarded as secondary cartilage according to current concepts. It is also argued that the hyaline-cell cartilage attached to the perichondral bone of the basioccipital (a cartilage bone), could also be viewed as secondary. The status of the cartilage on the nasal and lacrimal bones is less clear, for it develops, at least in part, from mucochondroid (mucous connective) tissue. This is the first definitive report of secondary cartilage in any lower vertebrate. The tissue is therefore not restricted to birds and mammals as hitherto believed, and a multipotential periosteum must have arisen early in vertebrate evolution. Images Fig. 1 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 11 Fig. 12 Fig. 13 Fig. 14 PMID:2481666

  10. Formation of protein induced micro-pores in Chitosan membranes

    Science.gov (United States)

    Begum, S. N. Suraiya; Aswal, V. K.; Ramasamy, Radha Perumal

    2017-05-01

    Polymer based nanocomposites are important class of materials and have wide applications. Blending two biopolymers can lead to the development of new materials with tailored properties. Chitosan is a naturally occurring polysaccharide with useful properties such as biodegradability and excellent film forming capacity. Bovine serum albumin (BSA) is a abundantly available globular protein. In our research the interaction of chitosan with BSA and the effect of formation of Au nanoparticles on chitosan-BSA system were investigated. Scanning electron microscope (SEM) of the films showed formation of micron sized pores and these pores were hindered with formation of Au nanoparticles. Small angle neutron scattering (SANS) analysis showed that BSA interacts with chitosan chain and affects the Rg value of chitosan. The formation of micro pores decreases the conductivity values (σ'), while the formation of Au nanoparticles increases σ'.

  11. Fluxes of water through aquaporin 9 weaken membrane-cytoskeleton anchorage and promote formation of membrane protrusions.

    Directory of Open Access Journals (Sweden)

    Thommie Karlsson

    Full Text Available All modes of cell migration require rapid rearrangements of cell shape, allowing the cell to navigate within narrow spaces in an extracellular matrix. Thus, a highly flexible membrane and a dynamic cytoskeleton are crucial for rapid cell migration. Cytoskeleton dynamics and tension also play instrumental roles in the formation of different specialized cell membrane protrusions, viz. lamellipodia, filopodia, and membrane blebs. The flux of water through membrane-anchored water channels, known as aquaporins (AQPs has recently been implicated in the regulation of cell motility, and here we provide novel evidence for the role of AQP9 in the development of various forms of membrane protrusion. Using multiple imaging techniques and cellular models we show that: (i AQP9 induced and accumulated in filopodia, (ii AQP9-associated filopodial extensions preceded actin polymerization, which was in turn crucial for their stability and dynamics, and (iii minute, local reductions in osmolarity immediately initiated small dynamic bleb-like protrusions, the size of which correlated with the reduction in osmotic pressure. Based on this, we present a model for AQP9-induced membrane protrusion, where the interplay of water fluxes through AQP9 and actin dynamics regulate the cellular protrusive and motile activity of cells.

  12. Membrane Formation on the Surface of implanted Posterior Chamber Intraocular Lenses

    Institute of Scientific and Technical Information of China (English)

    FangyaoYang; GuijunWu

    1995-01-01

    Purpose:To study the prevention and treatment of the membrane formation on the lens surface after extracapsular cataract extraction(ECCE)with posterior chamber intraocular lens(PCIOL)implantation.Methods:We reviewed the records of 312 cataractous patients that had undergone ECCEwith PCIOLimplantation between1989and1993,Postoperatively all pa-tients were examined under slit-lamp microscopy.The membrane formation on the surface of PCIOLin pupilar area was divided into four grades.Two mem-branes of surgical removal were observed under a transmission electrom mi-croscopy.One PCIOLof surgical removal was observed under a scanning electron microscopy.Results;Of312 patients,21 had the membrane formation on the surface of the PCIOL postoperatively.The incidence of the membrane formation was6.7%.Comparisone with cases of senile cataract showed the incidence to be significantly the highest among;1.patients who had traumatic cataract(P<0.05);2.pa-tients with complicated cataract(P<0.05).Interoperatively residual lens corten and rupture of posterior capsule,interval time betwwen the first and second eye operations less than 1month are the main factors of menbrane formation.The ultrastructure in membrane and cytology on the lens surface showed that the membrane on the surface of PCIOLs is usually composed of acellular protein film and cellular elements,including macrophages.fibroblast-like cells,epithelioid cells,giant cells,fibroblasts and collagen fibrils,etc.Conclusions:The cellular response on the surface of an implanted PCIOLis a chonic foreign-body inflammatory reaction and the membrane of the surfaceof implanted PCIOL is a reactive membrane of the foreign-body.Eye Science1995;11:131-135.

  13. Axon-glia interaction and membrane traffic in myelin formation.

    Science.gov (United States)

    White, Robin; Krämer-Albers, Eva-Maria

    2014-01-06

    In vertebrate nervous systems myelination of neuronal axons has evolved to increase conduction velocity of electrical impulses with minimal space and energy requirements. Myelin is formed by specialized glial cells which ensheath axons with a lipid-rich insulating membrane. Myelination is a multi-step process initiated by axon-glia recognition triggering glial polarization followed by targeted myelin membrane expansion and compaction. Thereby, a myelin sheath of complex subdomain structure is established. Continuous communication between neurons and glial cells is essential for myelin maintenance and axonal integrity. A diverse group of diseases, from multiple sclerosis to schizophrenia, have been linked to malfunction of myelinating cells reflecting the physiological importance of the axon-glial unit. This review describes the mechanisms of axonal signal integration by oligodendrocytes emphasizing the central role of the Src-family kinase Fyn during central nervous system (CNS) myelination. Furthermore, we discuss myelin membrane trafficking with particular focus on endocytic recycling and the control of proteolipid protein (PLP) transport by soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins. Finally, PLP mistrafficking is considered in the context of myelin diseases.

  14. Axon-glia interaction and membrane traffic in myelin formation

    Directory of Open Access Journals (Sweden)

    Robin eWhite

    2014-01-01

    Full Text Available In vertebrate nervous systems myelination of neuronal axons has evolved to increase conduction velocity of electrical impulses with minimal space and energy requirements. Myelin is formed by specialised glial cells which ensheath axons with a lipid-rich insulating membrane. Myelination is a multi-step process initiated by axon-glia recognition triggering glial polarisation followed by targeted myelin membrane expansion and compaction. Thereby, a myelin sheath of complex subdomain structure is established. Continuous communication between neurons and glial cells is essential for myelin maintenance and axonal integrity. A diverse group of diseases, from multiple sclerosis to schizophrenia, have been linked to malfunction of myelinating cells reflecting the physiological importance of the axon-glial unit. This review describes the mechanisms of axonal signal integration by oligodendrocytes emphasising the central role of the Src-family kinase Fyn during CNS myelination. Furthermore, we discuss myelin membrane trafficking with particular focus on endocytic recycling and the control of PLP (proteolipid protein transport by SNARE proteins. Finally, PLP mistrafficking is considered in the context of myelin diseases.

  15. Microstructures in phase-inversion membranes. Part I. Formation of macrovoids

    NARCIS (Netherlands)

    Smolders, C.A.; Smolders, C.A.; Reuvers, A.J.; Reuvers, A.J.; Boom, R.M.; Boom, R.M.; Wienk, I.M.; Wienk, I.M.

    1992-01-01

    A new mechanism for the formation of macrovoids in phase-inversion membranes is proposed. It is based on the observed difference in type of demixing of a thin film of a polymer solution when immersed in a nonsolvent bath: delayed or instantaneous demixing. The explanation for macrovoid formation ass

  16. Cake layer formation in anaerobic submerged membrane bioreactors (AnSMBR) for wastewater treatment

    NARCIS (Netherlands)

    Jeison, D.; Lier, van J.B.

    2006-01-01

    Cake layer formation in anaerobic gas-sparged submerged membrane bioreactors was studied using the critical flux concept, at 30 and 55 °C. The impact of biomass concentration, from 25 to 50 g TSS/L, and superficial gas velocity, up to 70 m/h, of over cake layer formation was studied, using response

  17. Role of Pseudomonas aeruginosa peptidoglycan-associated outer membrane proteins in vesicle formation.

    Science.gov (United States)

    Wessel, Aimee K; Liew, Jean; Kwon, Taejoon; Marcotte, Edward M; Whiteley, Marvin

    2013-01-01

    Gram-negative bacteria produce outer membrane vesicles (OMVs) that package and deliver proteins, small molecules, and DNA to prokaryotic and eukaryotic cells. The molecular details of OMV biogenesis have not been fully elucidated, but peptidoglycan-associated outer membrane proteins that tether the outer membrane to the underlying peptidoglycan have been shown to be critical for OMV formation in multiple Enterobacteriaceae. In this study, we demonstrate that the peptidoglycan-associated outer membrane proteins OprF and OprI, but not OprL, impact production of OMVs by the opportunistic pathogen Pseudomonas aeruginosa. Interestingly, OprF does not appear to be important for tethering the outer membrane to peptidoglycan but instead impacts OMV formation through modulation of the levels of the Pseudomonas quinolone signal (PQS), a quorum signal previously shown by our laboratory to be critical for OMV formation. Thus, the mechanism by which OprF impacts OMV formation is distinct from that for other peptidoglycan-associated outer membrane proteins, including OprI.

  18. A cell-free scaffold-based cartilage repair provides improved function hyaline-like repair at one year.

    Science.gov (United States)

    Siclari, Alberto; Mascaro, Gennaro; Gentili, Chiara; Cancedda, Ranieri; Boux, Eugenio

    2012-03-01

    Bone marrow stimulation techniques in cartilage repair such as drilling are limited by the formation of fibrous to hyaline-like repair tissue. It has been suggested such techniques can be enhanced by covering the defect with scaffolds. We present an innovative approach using a polyglycolic acid (PGA)-hyaluronan scaffold with platelet-rich-plasma (PRP) in drilling. We asked whether (1) PRP immersed in a cell-free PGA-hyaluronan scaffold improves patient-reported 1-year outcomes for the Knee injury and Osteoarthritis Score (KOOS), and (2) implantation of the scaffold in combination with bone marrow stimulation leads to the formation of hyaline-like cartilage repair tissue. We reviewed 52 patients who had arthroscopic implantation of the PGA-hyaluronan scaffold immersed with PRP in articular cartilage defects of the knee pretreated with Pridie drilling. Patients were assessed by KOOS. At 9 months followup, histologic staining was performed in specimens obtained from five patients to assess the repair tissue quality. The KOOS subscores improved for pain (55 to 91), symptoms (57 to 88), activities of daily living (69 to 86), sports and recreation (36 to 70), and quality of life (38 to 73). The histologic evaluation showed a homogeneous hyaline-like cartilage repair tissue. The cell-free PGA-hyaluronan scaffold combined with PRP leads to cartilage repair and improved patient-reported outcomes (KOOS) during 12 months of followup. Histologic sections showed morphologic features of hyaline-like repair tissue. Long-term followup is needed to determine if the cartilage repair tissue is durable. Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

  19. ULTRAFILTRATION MEMBRANE FORMATION OF PES-C, PES AND PPESK POLYMERS WITH DIFFERENT SOLVENTS

    Institute of Scientific and Technical Information of China (English)

    Wei-na Sun; Cui-xian Chen; Ji-ding Li; Yang-zheng Lin

    2009-01-01

    Ultrafiltration membranes were prepared using phenolphthalein polyarylethersulfone (PES-C),polyethersulfone (PES) and poly(phthalazinone ether sulfone ketone) (PPESK) as polymers and NMP,DMAc,DMF and DMSO as solvents by immersion precipitation via phase inversion.Experimental data of thermodynamic properties of the polymer solutions and kinetic process of membrane formation were reported.For polymer solutions with good solvents,the sequence of the viscous flow activation energy (Eη) was coincident with that of the viscosity (η),without depending on the dissolving power of the solvents (characterized by intrinsic viscosity ([η]).The cloud point of the dilute polymer solutions was related to [η] of the polymer and gave a strong influence on the gelation rate in membrane formation process.The pure water flux (J) and the bovine serum albumin (BSA) rejection (R) of PES-C,PES and PPESK membranes were measured,the pure water flux (J) of membranes significantly depended on the gelation rate.The open porosity (OP) and the maximum pore size of membrane surface were calculated,and the relationship between membrane performance and membrane pore structure was discussed.

  20. In situ formation of stable gold nanoparticles in polymer inclusion membranes.

    Science.gov (United States)

    Kumar, Rakesh; Pandey, Ashok K; Tyagi, A K; Dey, G K; Ramagiri, Shobha V; Bellare, Jayesh R; Goswami, A

    2009-09-15

    Gold nanoparticles (Au nps) were synthesized in the matrix of a plasticized anion-exchange membrane. The membrane was prepared by solvent casting of the solution containing a liquid anion exchanger trioctylmethylammonium chloride (Aliquat-336), a matrix-forming polymer cellulose triacetate (CTA), and a plasticizer dioctyl phthalate (DOP) dissolved in CH(2)Cl(2). For in situ synthesis of Au nps, the membrane samples were equilibrated with a well-stirred solution containing 0.01 mol L(-1)HAuCl(4). AuCl(4)(-) ions were transferred to membrane matrix as an ion pair with Aliquat-336 by an ion-exchange mechanism. In a second step, AuCl(4)(-) ion-loaded membrane samples were placed in a well-stirred 0.1 mol L(-1) aqueous solution of NaBH(4) for reduction. It was observed that 80% of the anion-exchange sites were readily available for the exchange process after formation of the Au nps. The content of Au nps in the membrane was increased either by increasing the concentration of the Aliquat-336 in membrane or by repeating sequential cycles of loading of AuCl(4)(-) ions followed by reduction with BH(4)(-) in the membrane matrix. TEM images of a cross section of the membrane showed that Au nps were dispersed throughout the matrix of the membrane but excluded from the surface. The size distribution of the nps was found to be dependent on Au content in the membrane. For example, 7- to 16-nm Au nps with average size 10 nm were observed in the membrane after the first cycle of synthesis. On increasing the Au content in the membrane by repeating the cycle of synthesis, the size dispersion of nps broadened from 5 to 20 nm without affecting the average size. The lambda(max) (530 nm) and intensity of the surface plasmon band of Au nps embedded in the matrix of membrane were found to remain unaltered over a testing period of a month in the samples kept in water as well as in air under ambient conditions. This indicated that Au nps were quite stable in the membrane matrix. The

  1. Generation of Scaffoldless Hyaline Cartilaginous Tissue from Human iPSCs

    Directory of Open Access Journals (Sweden)

    Akihiro Yamashita

    2015-03-01

    Full Text Available Defects in articular cartilage ultimately result in loss of joint function. Repairing cartilage defects requires cell sources. We developed an approach to generate scaffoldless hyaline cartilage from human induced pluripotent stem cells (hiPSCs. We initially generated an hiPSC line that specifically expressed GFP in cartilage when teratoma was formed. We optimized the culture conditions and found BMP2, transforming growth factor β1 (TGF-β1, and GDF5 critical for GFP expression and thus chondrogenic differentiation of the hiPSCs. The subsequent use of scaffoldless suspension culture contributed to purification, producing homogenous cartilaginous particles. Subcutaneous transplantation of the hiPSC-derived particles generated hyaline cartilage that expressed type II collagen, but not type I collagen, in immunodeficiency mice. Transplantation of the particles into joint surface defects in immunodeficiency rats and immunosuppressed mini-pigs indicated that neocartilage survived and had potential for integration into native cartilage. The immunodeficiency mice and rats suffered from neither tumors nor ectopic tissue formation. The hiPSC-derived cartilaginous particles constitute a viable cell source for regenerating cartilage defects.

  2. Changes of rabbit meniscus influenced by hyaline cartilage injury of osteoarthritis.

    Science.gov (United States)

    Zhao, Jiajun; Huang, Suizhu; Zheng, Jia; Zhong, Chunan; Tang, Chao; Zheng, Lei; Zhang, Zhen; Xu, Jianzhong

    2014-01-01

    Osteoarthritis (OA) is a common disease in the elderly population. Most of the previous OA-related researches focused on articular cartilage degeneration, osteophyte formation and synovitis etc. However, the role of the meniscus in these pathological changes has not been given enough attention. The goal of our study was to find the pathological changes of the meniscus in OA knee and determine their relationship. 20 months old female Chinese rabbits received either knee damaging operations with articular cartilage scratch method or sham operation randomly on one of their knees. They were sacrificed after 1-6 weeks post-operation. Medial Displacement Index (MDI) for meniscus dislocation, hematoxylin and eosin (HE) for routine histological evaluation, Toluidine blue (TB) stains for evaluating proteoglycans were carried out. Immunohistochemical (IHC) staining was performed with a two-step detection kit. Histological analysis showed chondrocyte clusters around cartilage lesions and moderate loss of proteoglycans in the operation model, as well as MDI increase and all characteristics of OA. High expression of MMP-3 and TIMP-1 also were found in both hyaline cartilage and meniscus. Biomechanical and biochemistry environment around the meniscus is altered when OA occur. If meniscus showed degeneration, subluxation and dysfunction, OA would be more severe. Prompt repair or reconstruction of hyaline cartilage in weight bearing area when it injured could prevent meniscus degeneration and subluxation, then prevent the development of OA.

  3. Generation of scaffoldless hyaline cartilaginous tissue from human iPSCs.

    Science.gov (United States)

    Yamashita, Akihiro; Morioka, Miho; Yahara, Yasuhito; Okada, Minoru; Kobayashi, Tomohito; Kuriyama, Shinichi; Matsuda, Shuichi; Tsumaki, Noriyuki

    2015-03-10

    Defects in articular cartilage ultimately result in loss of joint function. Repairing cartilage defects requires cell sources. We developed an approach to generate scaffoldless hyaline cartilage from human induced pluripotent stem cells (hiPSCs). We initially generated an hiPSC line that specifically expressed GFP in cartilage when teratoma was formed. We optimized the culture conditions and found BMP2, transforming growth factor β1 (TGF-β1), and GDF5 critical for GFP expression and thus chondrogenic differentiation of the hiPSCs. The subsequent use of scaffoldless suspension culture contributed to purification, producing homogenous cartilaginous particles. Subcutaneous transplantation of the hiPSC-derived particles generated hyaline cartilage that expressed type II collagen, but not type I collagen, in immunodeficiency mice. Transplantation of the particles into joint surface defects in immunodeficiency rats and immunosuppressed mini-pigs indicated that neocartilage survived and had potential for integration into native cartilage. The immunodeficiency mice and rats suffered from neither tumors nor ectopic tissue formation. The hiPSC-derived cartilaginous particles constitute a viable cell source for regenerating cartilage defects. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  4. Pulmonary hyalinizing granuloma and retroperitoneal fibrosis in an adolescent

    Energy Technology Data Exchange (ETDEWEB)

    Young, Adam S.; Binkovitz, Larry A.; Adler, Brent H. [Columbus Children' s Hospital, Children' s Radiological Institute, Columbus, OH (United States); Nicol, Kathleen K. [Columbus Children' s Hospital, Department of Pathology, Columbus, OH (United States); Rennebohm, Robert M. [Columbus Children' s Hospital, Department of Rheumatology, Columbus, OH (United States)

    2007-01-15

    We describe a 15-year-old boy who developed pulmonary hyalinizing granuloma (PHG) and retroperitoneal fibrosis (RPF). His PHG and RPF were not associated with histoplasmosis or tuberculosis and appeared to represent idiopathic autoimmune phenomena. This is the first reported case of PHG in a pediatric patient and the fourth reported co-occurrence of PHG and RPF. The use of F-18 fluorodeoxyglucose positron emission tomography in the diagnostic and follow-up evaluation of PHG is reported. (orig.)

  5. Track-etched membrane: dynamics of pore formation

    Science.gov (United States)

    Ferain, E.; Legras, R.

    1994-02-01

    The dynamics of pore formation during etching of heavy ion (Ar 9+ - 4.5 MeV/amu) irradiated bisphenol-A polycarbonate (PC) and polyethylene terephthalate (PET) films is determined by a conductivity cell. This work presents the theoretical basis of this method and describes the experimental procedure. The obtained results allow the determination of the track ( Vt) and bulk ( Vg) etch rates, and an estimate of the damage zone diameter in PC before etching.

  6. Spontaneous formation of structurally diverse membrane channel architectures from a single antimicrobial peptide

    Science.gov (United States)

    Wang, Yukun; Chen, Charles H.; Hu, Dan; Ulmschneider, Martin B.; Ulmschneider, Jakob P.

    2016-11-01

    Many antimicrobial peptides (AMPs) selectively target and form pores in microbial membranes. However, the mechanisms of membrane targeting, pore formation and function remain elusive. Here we report an experimentally guided unbiased simulation methodology that yields the mechanism of spontaneous pore assembly for the AMP maculatin at atomic resolution. Rather than a single pore, maculatin forms an ensemble of structurally diverse temporarily functional low-oligomeric pores, which mimic integral membrane protein channels in structure. These pores continuously form and dissociate in the membrane. Membrane permeabilization is dominated by hexa-, hepta- and octamers, which conduct water, ions and small dyes. Pores form by consecutive addition of individual helices to a transmembrane helix or helix bundle, in contrast to current poration models. The diversity of the pore architectures--formed by a single sequence--may be a key feature in preventing bacterial resistance and could explain why sequence-function relationships in AMPs remain elusive.

  7. Three new species of Trichoderma with hyaline ascospores from China.

    Science.gov (United States)

    Zhu, Z X; Zhuang, W Y

    2015-01-01

    Collections of Trichoderma having hyaline ascospores from different areas of China were examined. Using combined analyses of morphological data, culture characters and phylogenetic information based on rDNA sequences of partial nuc translation elongation factor 1-α encoding gene (TEF1-α) and the gene encoding the second largest nuc RNA polymerase subunit (RPB2), three new species, Trichoderma applanatum, T. oligosporum and T. sinoluteum, were discovered and are described. Trichoderma applanatum produces continuous flat to pulvinate, white to cream stromata with dense orange or pale brown ostioles, and simple acremonium-like to verticillium-like conidiophores, belongs to the Hypocreanum clade and is closely related to T. decipiens. Trichoderma oligosporum forms reddish brown stromata with a downy surface, hyaline conidia and gliocladium-like conidiophores, and is closely related to but distinct from T. crystalligenum in the Psychrophila clade. Trichoderma sinoluteum, as a member of the Polysporum clade, is characterized by pale yellow stromata, white pustulate conidiomata, pachybasium-like conidiophores, and hyaline conidia. Differences between the new species and their close relatives are discussed.

  8. Pulmonary Hyalinizing Granuloma Associated with Idiopathic Thrombocytopenic Purpura

    Directory of Open Access Journals (Sweden)

    Christopher Coleman

    2014-01-01

    Full Text Available Pulmonary hyalinizing granuloma (PHG is a rare, benign lung disease of unknown etiology. It manifests as discrete, rounded nodules within the lung parenchyma. A 39-year-old woman presented for investigation after pulmonary nodules were found incidentally. Chest computed tomography showed multiple, discrete, non-enhancing pulmonary nodules bilaterally. Positron emission tomography (PET was negative. Biopsy demonstrated a non-specific lymphoplasmacytic infiltrate. Open resection yielded two nodules consistent with hyalinizing granulomas. The differential for multiple pulmonary nodules is broad. PET scan can help rule out metastatic disease, although some cancers are not hypermetabolic on PET. Furthermore, some non-malignant conditions, including hyalinizing granuloma, can show increased activity on PET. PHG should be included in the differential of multiple pulmonary nodules, especially if nodule stability can be demonstrated and/or needle biopsies are non-diagnostic. Associated immune-mediated conditions, such as idiopathic thrombocytopenic purpura (ITP in our patient, may also favor HG. In this case report we find an association between PHG and ITP.

  9. Multicentric hyaline-vascular Castleman's disease in the retroperitoneum

    Institute of Scientific and Technical Information of China (English)

    Li-Ying Wang; Tian-An Jiang; Xiao-Dong Teng; Qi-Yu Zhao; Fen Chen

    2009-01-01

    BACKGROUND: Castleman's disease is a rare lymphopro-liferative disease of unknown cause. Most multicentric cases described have been of the plasma-cell variety. This article presents a case of multicentric hyaline-vascular Castleman's disease in the retroperitoneum with the ultrasonographic and computed tomography (CT) imaging manifestations. METHODS: During routine physical examination, a mass was detected in the left abdomen of a 53-year-old man with no signs or symptoms. The patient underwent ultrasound-guided aspiration biopsy and operative excision after laboratory examination, ultrasonography, and CT. RESULTS: Ultrasonography demonstrated a dominant hypoechogenic mass with hypervascularity in the retroperitoneum. CT detected a relatively homogenous enhanced lesion and several satellite nodules. After the mass and several lymph nodes were resected, histopathologic examination demonstrated a lymphocyte-predominant infiltrate surrounding the germinal centres and extensive capillary proliferation, consistent with the hyaline-vascular type of Castleman's disease. The patient received postoperative chemotherapy and remained free of recurrence 3 months later. CONCLUSION: Ultrasonography and contrast-enhanced CT can provide a positive differential diagnosis of hyaline-vascular Castleman's disease which is a kind of giant lymph node hyperplasia with hypervascularity.

  10. Methylprednisolone microsphere sustained-release membrane inhibits scar formation at the site of peripheral nerve lesion

    Institute of Scientific and Technical Information of China (English)

    Qiang Li; Teng Li; Xiang-chang Cao; De-qing Luo; Ke-jian Lian

    2016-01-01

    Corticosteroids are widely used for the treatment of acute central nervous system injury. However, their bioactivity is limited by their short half-life. Sustained release of glucocorticoids can prolong their efifcacy and inhibit scar formation at the site of nerve injury. In the present study, we wrapped the anastomotic ends of the rat sciatic nerve with a methylprednisolone sustained-release membrane. Compared with methylprednisone alone or methylprednisone microspheres, the methylprednisolone microsphere sustained-release membrane reduced tissue adhesion and inhibited scar tissue formation at the site of anastomosis. It also increased sciatic nerve function index and the thick-ness of the myelin sheath. Our ifndings show that the methylprednisolone microsphere sustained-release membrane effectively inhibits scar formation at the site of anastomosis of the peripheral nerve, thereby promoting nerve regeneration.

  11. Clinical research of different ventilation modes combined with pulmonary surfactant and ;mucosolvan in the treatment of preterm newborns with hyaline membrane disease%不同通气模式联合肺表面活性物质、沐舒坦治疗早产儿肺透明膜病的临床研究

    Institute of Scientific and Technical Information of China (English)

    吴杰斌; 周彬; 翟敬芳; 金宝; 张艳艳

    2015-01-01

    Objective To investigate the clinical application effect of different ventilation modes combined with pulmonary surfactant and mucosolvan in the treatment of preterm newborns with hyaline membrane disease (HMD). Methods 76 cases of preterm infants with HMD (Ⅲ-Ⅳgrade) from Xuzhou central hospital neonatal intensive care unit (neonatal intensive care unit, NICU) from 2013 January to 2015 February were randomly divided into two group, high frequency oscillatory ventilation (HFOV) group 40 cases and conventional mechanical ventilation (CMV) group 36 cases, at the beginning of mechanical ventilation, the two groups began to use the pulmonary surfactant (PS), while HFOV group used intravenous mucosolvan 30 mg/kg daily. The main observation was the comparison of blood gas indicators before and after mechanical ventilator, the indicators changes of related respiratory function and the complication rate, et al. Results PaO2, PaO2/FiO2, Oxygenation index (OI=100×MAP×FiO2/ PaO2) and arterial/alveolar oxygen partial pressure ratio (713×FiO2-PaCO2/0.8) were improved significantly in HFOV group compared with CMV group (P<0.05). There was no statistical significance between both groups in the number of deaths, ventilation time, gas leak syndrome, bronchopulmonary dysplasia (BPD), retinopathy of premature children (ROP), intraventricular hemorrhage (IVH) and periventricular leukomalacia (PVL). Conclusion High-frequency oscillatory ventilation mode combined with pulmonary surfactant and mucosolvan could improve arterial blood gas index and respiratory function index and improve oxygenation, it has application value and should be applied extensively.%目的:观察不同通气模式联合肺表面活性物质(PS)、沐舒坦治疗早产儿肺透明膜病的疗效。方法收集2013年1月至2015年2月徐州市中心医院新生儿重症监护病房(NICU)收治76例患肺透明膜病(HMD)(Ⅲ~Ⅳ级)机械通气早产儿,采用随机数字表法将患

  12. Septal membrane fusion--a pivotal event in bacterial spore formation?

    Science.gov (United States)

    Higgins, M L; Piggot, P J

    1992-09-01

    Formation of the asymmetrically located septum divides sporulating bacilli into two distinct cells: the mother cell and the prespore. The rigidifying wall material in the septum is subsequently removed by autolysis. Examination of published electron micrographs indicates that the two septal membranes then fuse to form a single membrane. Membrane fusion would be expected to have profound consequences for subsequent development. For example, it is suggested that fusion activates processing of pro-sigma E to sigma E in the cytoplasm by exposing it to a membrane-bound processing enzyme. Asymmetry of the fused membrane could restrict processing to one face of the membrane and hence explain why sigma E is associated with transcription in the mother cell but not in the prespore. Asymmetry of the fused membrane might also provide a mechanism for restricting the activity of another factor, sigma F, to the prespore. Attachment of the flexible fused septal membrane to the condensing prespore nucleoid could help drive the engulfment of the prespore by the mother cell.

  13. Molecular aspects of polyene- and sterol-dependent pore formation in thin lipid membranes.

    Science.gov (United States)

    Dennis, V W; Stead, N W; Andreoli, T E

    1970-03-01

    Amphotericin B modifies the permeability properties of thin lipid membranes formed from solutions containing sheep red cell phospholipids and cholesterol. At 10(-6)M amphotericin B, the DC membrane resistance fell from approximately 10(8) to approximately 10(2) ohm-cm(2), and the membranes became Cl(-)-, rather than Na(+)-selective; the permeability coefficients for hydrophilic nonelectrolytes increased in inverse relationship to solute size, and the rate of water flow during osmosis increased 30-fold. These changes may be rationalized by assuming that the interaction of amphotericin B with membrane-bound sterol resulted in the formation of aqueous pores. N-acetylamphotericin B and the methyl ester of N-acetylamphotericin B, but not the smaller ring compounds, filipin, rimocidin, and PA-166, produced comparable permeability changes in identical membranes, and amphotericin B and its derivatives produced similar changes in the properties of membranes formed from phospholipid-free sterol solutions. However, amphotericin B did not affect ionic selectivity or water and nonelectrolyte permeability in membranes formed from solutions containing phospholipids and no added cholesterol, or when cholesterol was replaced by either cholesterol palmitate, dihydrotachysterol, epicholesterol, or Delta5-cholesten-3-one. Phospholipid-free sterol membranes exposed to amphotericin B or its derivatives were anion-selective, but the degree of Cl(-) selectivity varied among the compounds, and with the aqueous pH. The data are discussed with regard to, first, the nature of the polyene-sterol interactions which result in pore formation, and second, the functional groups on amphotericin B responsible for membrane anion selectivity.

  14. Trapping of Vibrio cholerae cytolysin in the membrane-bound monomeric state blocks membrane insertion and functional pore formation by the toxin.

    Science.gov (United States)

    Rai, Anand Kumar; Chattopadhyay, Kausik

    2014-06-13

    Vibrio cholerae cytolysin (VCC) is a potent membrane-damaging cytolytic toxin that belongs to the family of β barrel pore-forming protein toxins. VCC induces lysis of its target eukaryotic cells by forming transmembrane oligomeric β barrel pores. The mechanism of membrane pore formation by VCC follows the overall scheme of the archetypical β barrel pore-forming protein toxin mode of action, in which the water-soluble monomeric form of the toxin first binds to the target cell membrane, then assembles into a prepore oligomeric intermediate, and finally converts into the functional transmembrane oligomeric β barrel pore. However, there exists a vast knowledge gap in our understanding regarding the intricate details of the membrane pore formation process employed by VCC. In particular, the membrane oligomerization and membrane insertion steps of the process have only been described to a limited extent. In this study, we determined the key residues in VCC that are critical to trigger membrane oligomerization of the toxin. Alteration of such key residues traps the toxin in its membrane-bound monomeric state and abrogates subsequent oligomerization, membrane insertion, and functional transmembrane pore-formation events. The results obtained from our study also suggest that the membrane insertion of VCC depends critically on the oligomerization process and that it cannot be initiated in the membrane-bound monomeric form of the toxin. In sum, our study, for the first time, dissects membrane binding from the subsequent oligomerization and membrane insertion steps and, thus, defines the exact sequence of events in the membrane pore formation process by VCC.

  15. Extracellular ultrathin fibers sensitive to intracellular reactive oxygen species: Formation of intercellular membrane bridges

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Se-Hui; Park, Jin-Young; Joo, Jung-Hoon; Kim, Young-Myeong; Ha, Kwon-Soo, E-mail: ksha@kangwon.ac.kr

    2011-07-15

    Membrane bridges are key cellular structures involved in intercellular communication; however, dynamics for their formation are not well understood. We demonstrated the formation and regulation of novel extracellular ultrathin fibers in NIH3T3 cells using confocal and atomic force microscopy. At adjacent regions of neighboring cells, phorbol 12-myristate 13-acetate (PMA) and glucose oxidase induced ultrathin fiber formation, which was prevented by Trolox, a reactive oxygen species (ROS) scavenger. The height of ROS-sensitive ultrathin fibers ranged from 2 to 4 nm. PMA-induced formation of ultrathin fibers was inhibited by cytochalasin D, but not by Taxol or colchicine, indicating that ultrathin fibers mainly comprise microfilaments. PMA-induced ultrathin fibers underwent dynamic structural changes, resulting in formation of intercellular membrane bridges. Thus, these fibers are formed by a mechanism(s) involving ROS and involved in formation of intercellular membrane bridges. Furthermore, ultrastructural imaging of ultrathin fibers may contribute to understanding the diverse mechanisms of cell-to-cell communication and the intercellular transfer of biomolecules, including proteins and cell organelles.

  16. Membrane Thickness Dependence of Nanopore Formation with a Focused Helium Ion Beam

    Directory of Open Access Journals (Sweden)

    Furat Sawafta

    2014-05-01

    Full Text Available Solid-state nanopores are emerging as a valuable tool for the detection and characterization of individual biomolecules. Central to their success is the realization of fabrication strategies that are both rapid and flexible in their ability to achieve diverse device dimensions. In this paper, we demonstrate the membrane thickness dependence of solid-state nanopore formation with a focused helium ion beam. We vary membrane thickness in situ and show that the rate of pore expansion follows a reproducible trend under all investigated membrane conditions. We show that this trend shifts to lower ion dose for thin membranes in a manner that can be described quantitatively, allowing devices of arbitrary dimension to be realized. Finally, we demonstrate that thin, small-diameter nanopores formed with our approach can be utilized for high signal-to-noise ratio resistive pulse sensing of DNA.

  17. Diffusion of solvent from a cast cellulose acetate solution during the formation of skinned membranes

    NARCIS (Netherlands)

    Altena, F.W.; Smid, J.; van den Berg, J.W.A.; Wijmans, J.G.; Smolders, C.A.

    1985-01-01

    The transport of solvent out of a cast cellulose acetate (CA) solution into the coagulation bath during membrane formation is treated as a diffusion process. From the increase of solvent concentration in the bath with time (solvent leaching experiments) an overall solvent diffusion coefficient has b

  18. Droplet formation in a T-shaped microchannel junction: A model system for membrane emulsification

    NARCIS (Netherlands)

    Graaf, van der S.; Steegmans, M.L.J.; Sman, van der R.G.M.; Schroën, C.G.P.H.; Boom, R.M.

    2005-01-01

    Droplet formation was studied in a glass microchip with a small channel containing to-be-dispersed phase perpendicular to a large channel with a cross-flowing continuous phase. This resembles the situation during cross-flow membrane emulsification. In this model system, droplets are formed at a

  19. Formation of nanopores in a SiN/SiO2 membrane with an electron beam

    NARCIS (Netherlands)

    Wu, M.Y.; Krapf, D.; Zandbergen, M.; Zandbergen, H.; Batson, P.E.

    2005-01-01

    An electron beam can drill nanopores in SiO2 or silicon nitride membranes and shrink a pore to a smaller diameter. Such nanopores are promising for single molecule detection. The pore formation in a 40 nm thick silicon nitride∕SiO2 bilayer using an electron beam with a diameter of 8 nm (full width o

  20. Biofilm formation on reverse osmosis membranes is initiated and dominated by Sphingomonas spp

    NARCIS (Netherlands)

    Bereschenko, L.A.; Stams, A.J.M.; Euverink, G.J.W.; Loosdrecht, M.C.M.

    2010-01-01

    The initial formation and spatiotemporal development of microbial biofilm layers on surfaces of new and clean reverse osmosis (RO) membranes and feed-side spacers were monitored in situ using flow cells placed in parallel with the RO system of a full-scale water treatment plant. The feed water of th

  1. Diffusion of solvent from a cast cellulose acetate solution during the formation of skinned membranes

    NARCIS (Netherlands)

    Altena, F.W.; Smid, J.; Berg, van den J.W.A.; Wijmans, J.G.; Smolders, C.A.

    1985-01-01

    The transport of solvent out of a cast cellulose acetate (CA) solution into the coagulation bath during membrane formation is treated as a diffusion process. From the increase of solvent concentration in the bath with time (solvent leaching experiments) an overall solvent diffusion coefficient has b

  2. Interleaflet Coupling, Pinning, and Leaflet Asymmetry—Major Players in Plasma Membrane Nanodomain Formation

    Science.gov (United States)

    Fujimoto, Toyoshi; Parmryd, Ingela

    2017-01-01

    The plasma membrane has a highly asymmetric distribution of lipids and contains dynamic nanodomains many of which are liquid entities surrounded by a second, slightly different, liquid environment. Contributing to the dynamics is a continuous repartitioning of components between the two types of liquids and transient links between lipids and proteins, both to extracellular matrix and cytoplasmic components, that temporarily pin membrane constituents. This make plasma membrane nanodomains exceptionally challenging to study and much of what is known about membrane domains has been deduced from studies on model membranes at equilibrium. However, living cells are by definition not at equilibrium and lipids are distributed asymmetrically with inositol phospholipids, phosphatidylethanolamines and phosphatidylserines confined mostly to the inner leaflet and glyco- and sphingolipids to the outer leaflet. Moreover, each phospholipid group encompasses a wealth of species with different acyl chain combinations whose lateral distribution is heterogeneous. It is becoming increasingly clear that asymmetry and pinning play important roles in plasma membrane nanodomain formation and coupling between the two lipid monolayers. How asymmetry, pinning, and interdigitation contribute to the plasma membrane organization is only beginning to be unraveled and here we discuss their roles and interdependence. PMID:28119914

  3. Relating performance of thin-film composite forward osmosis membranes to support layer formation and structure

    KAUST Repository

    Tiraferri, Alberto

    2011-02-01

    Osmotically driven membrane processes have the potential to treat impaired water sources, desalinate sea/brackish waters, and sustainably produce energy. The development of a membrane tailored for these processes is essential to advance the technology to the point that it is commercially viable. Here, a systematic investigation of the influence of thin-film composite membrane support layer structure on forward osmosis performance is conducted. The membranes consist of a selective polyamide active layer formed by interfacial polymerization on top of a polysulfone support layer fabricated by phase separation. By systematically varying the conditions used during the casting of the polysulfone layer, an array of support layers with differing structures was produced. The role that solvent quality, dope polymer concentration, fabric layer wetting, and casting blade gate height play in the support layer structure formation was investigated. Using a 1M NaCl draw solution and a deionized water feed, water fluxes ranging from 4 to 25Lm-2h-1 with consistently high salt rejection (>95.5%) were produced. The relationship between membrane structure and performance was analyzed. This study confirms the hypothesis that the optimal forward osmosis membrane consists of a mixed-structure support layer, where a thin sponge-like layer sits on top of highly porous macrovoids. Both the active layer transport properties and the support layer structural characteristics need to be optimized in order to fabricate a high performance forward osmosis membrane. © 2010 Elsevier B.V.

  4. Ionic Liquids As Self-Assembly Guide for the Formation of Nanostructured Block Copolymer Membranes

    KAUST Repository

    Madhavan, Poornima

    2015-04-30

    Nanostructured block copolymer membranes were manufactured by water induced phase inversion, using ionic liquids (ILs) as cosolvents. The effect of ionic liquids on the morphology was investigated, by using polystyrene-b-poly(4-vinyl pyridine) (PS-b-PV4P) diblock as membrane copolymer matrix and imidazolium and pyridinium based ILs. The effect of IL concentration and chemical composition was evident with particular interaction with P4VP blocks. The order of block copolymer/ILs solutions previous to the membrane casting was confirmed by cryo scanning electron microscopy and the morphologies of the manufactured nanostructured membranes were characterized by transmission and scanning electron microscopy. Non-protic ionic liquids facilitate the formation of hexagonal nanoporous block copolymer structure, while protic ILs led to a lamella-structured membrane. The rheology of the IL/block copolymer solutions was investigated, evaluating the storage and loss moduli. Most membranes prepared with ionic liquid had higher water flux than pure block copolymer membranes without additives.

  5. Cardiolipin plays an essential role in the formation of intracellular membranes in Escherichia coli.

    Science.gov (United States)

    Carranza, Gerardo; Angius, Federica; Ilioaia, Oana; Solgadi, Audrey; Miroux, Bruno; Arechaga, Ignacio

    2017-06-01

    Mitochondria, chloroplasts and photosynthetic bacteria are characterized by the presence of complex and intricate membrane systems. In contrast, non-photosynthetic bacteria lack membrane structures within their cytoplasm. However, large scale over-production of some membrane proteins, such as the fumarate reductase, the mannitol permease MtlA, the glycerol acyl transferase PlsB, the chemotaxis receptor Tsr or the ATP synthase subunit b, can induce the proliferation of intra cellular membranes (ICMs) in the cytoplasm of Escherichia coli. These ICMs are particularly rich in cardiolipin (CL). Here, we have studied the effect of CL in the generation of these membranous structures. We have deleted the three genes (clsA, clsB and clsC) responsible of CL biosynthesis in E. coli and analysed the effect of these mutations by fluorescent and electron microscopy and by lipid mass spectrometry. We have found that CL is essential in the formation of non-lamellar structures in the cytoplasm of E. coli cells. These results could help to understand the structuration of membranes in E. coli and other membrane organelles, such as mitochondria and ER. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Hyaline Articular Matrix Formed by Dynamic Self-Regenerating Cartilage and Hydrogels.

    Science.gov (United States)

    Meppelink, Amanda M; Zhao, Xing; Griffin, Darvin J; Erali, Richard; Gill, Thomas J; Bonassar, Lawrence J; Redmond, Robert W; Randolph, Mark A

    2016-07-01

    Injuries to the articular cartilage surface are challenging to repair because cartilage possesses a limited capacity for self-repair. The outcomes of current clinical procedures aimed to address these injuries are inconsistent and unsatisfactory. We have developed a novel method for generating hyaline articular cartilage to improve the outcome of joint surface repair. A suspension of 10(7) swine chondrocytes was cultured under reciprocating motion for 14 days. The resulting dynamic self-regenerating cartilage (dSRC) was placed in a cartilage ring and capped with fibrin and collagen gel. A control group consisted of chondrocytes encapsulated in fibrin gel. Constructs were implanted subcutaneously in nude mice and harvested after 6 weeks. Gross, histological, immunohistochemical, biochemical, and biomechanical analyses were performed. In swine patellar groove, dSRC was implanted into osteochondral defects capped with collagen gel and compared to defects filled with osteochondral plugs, collagen gel, or left empty after 6 weeks. In mice, the fibrin- and collagen-capped dSRC constructs showed enhanced contiguous cartilage matrix formation over the control of cells encapsulated in fibrin gel. Biochemically, the fibrin and collagen gel dSRC groups were statistically improved in glycosaminoglycan and hydroxyproline content compared to the control. There was no statistical difference in the biomechanical data between the dSRC groups and the control. The swine model also showed contiguous cartilage matrix in the dSRC group but not in the collagen gel and empty defects. These data demonstrate the survivability and successful matrix formation of dSRC under the mechanical forces experienced by normal hyaline cartilage in the knee joint. The results from this study demonstrate that dSRC capped with hydrogels successfully engineers contiguous articular cartilage matrix in both nonload-bearing and load-bearing environments.

  7. Juvenile hyaline fibromatosis. Radiological diagnosis. Fibromatosis hialina juvenil. Diagnostico radiologico

    Energy Technology Data Exchange (ETDEWEB)

    Fuentes, R.; Sar, V.; Cabrera, J.J.; Diaz, L.; Hernandez, B.; Valeron, P.; Baez, O.; Rodriguez, M.

    1993-10-01

    Juvenile hyaline fibromatosis (JHF) is a rare disorder of unknown etiology, very few cases of which have been reported in the literature. It presents similarities to other fibromatosys, but has its particular radiological features which differentiate it from them. The clinical findings consist of several, slow growing, subcutaneous nodules, flexion contractures of the joints which can lead to disability, gingival hypertrophy and muscular atrophy. The suspected radiological diagnosis is confirmed by electron microscopy study of the nodules, although light microscopy can also reveal suggestive images. Author (9 refs.)

  8. Formation of cholesterol bilayer domains precedes formation of cholesterol crystals in cholesterol/dimyristoylphosphatidylcholine membranes: EPR and DSC studies.

    Science.gov (United States)

    Mainali, Laxman; Raguz, Marija; Subczynski, Witold K

    2013-08-01

    Saturation-recovery EPR along with DSC were used to determine the cholesterol content at which pure cholesterol bilayer domains (CBDs) and cholesterol crystals begin to form in dimyristoylphosphatidylcholine (DMPC) membranes. To preserve compositional homogeneity throughout the membrane suspension, lipid multilamellar dispersions were prepared using a rapid solvent exchange method. The cholesterol content increased from 0 to 75 mol %. With spin-labeled cholesterol analogues, it was shown that the CBDs begin to form at ~50 mol % cholesterol. It was confirmed by DSC that the cholesterol solubility threshold for DMPC membranes is detected at ~66 mol % cholesterol. At levels above this cholesterol content, monohydrate cholesterol crystals start to form. The major finding is that the formation of CBDs precedes formation of cholesterol crystals. The region of the phase diagram for cholesterol contents between 50 and 66 mol % is described as a structured one-phase region in which CBDs have to be supported by the surrounding DMPC bilayer saturated with cholesterol. Thus, the phase boundary located at 66 mol % cholesterol separates the structured one-phase region (liquid-ordered phase of DMPC with CBDs) from the two-phase region where the structured liquid-ordered phase of DMPC coexists with cholesterol crystals. It is likely that CBDs are precursors of monohydrate cholesterol crystals.

  9. Membrane Incorporation, Channel Formation, and Disruption of Calcium Homeostasis by Alzheimer's β-Amyloid Protein

    Directory of Open Access Journals (Sweden)

    Masahiro Kawahara

    2011-01-01

    Full Text Available Oligomerization, conformational changes, and the consequent neurodegeneration of Alzheimer's β-amyloid protein (AβP play crucial roles in the pathogenesis of Alzheimer's disease (AD. Mounting evidence suggests that oligomeric AβPs cause the disruption of calcium homeostasis, eventually leading to neuronal death. We have demonstrated that oligomeric AβPs directly incorporate into neuronal membranes, form cation-sensitive ion channels (“amyloid channels”, and cause the disruption of calcium homeostasis via the amyloid channels. Other disease-related amyloidogenic proteins, such as prion protein in prion diseases or α-synuclein in dementia with Lewy bodies, exhibit similarities in the incorporation into membranes and the formation of calcium-permeable channels. Here, based on our experimental results and those of numerous other studies, we review the current understanding of the direct binding of AβP into membrane surfaces and the formation of calcium-permeable channels. The implication of composition of membrane lipids and the possible development of new drugs by influencing membrane properties and attenuating amyloid channels for the treatment and prevention of AD is also discussed.

  10. The Role of Membrane Fluidization in the Gel-Assisted Formation of Giant Polymersomes.

    Science.gov (United States)

    Greene, Adrienne C; Henderson, Ian M; Gomez, Andrew; Paxton, Walter F; VanDelinder, Virginia; Bachand, George D

    2016-01-01

    Polymersomes are being widely explored as synthetic analogs of lipid vesicles based on their enhanced stability and potential uses in a wide variety of applications in (e.g., drug delivery, cell analogs, etc.). Controlled formation of giant polymersomes for use in membrane studies and cell mimetic systems, however, is currently limited by low-yield production methodologies. Here, we describe for the first time, how the size distribution of giant poly(ethylene glycol)-poly(butadiene) (PEO-PBD) polymersomes formed by gel-assisted rehydration may be controlled based on membrane fluidization. We first show that the average diameter and size distribution of PEO-PBD polymersomes may be readily increased by increasing the temperature of the rehydration solution. Further, we describe a correlative relationship between polymersome size and membrane fluidization through the addition of sucrose during rehydration, enabling the formation of PEO-PBD polymersomes with a range of diameters, including giant-sized vesicles (>100 μm). This correlative relationship suggests that sucrose may function as a small molecule fluidizer during rehydration, enhancing polymer diffusivity during formation and increasing polymersome size. Overall the ability to easily regulate the size of PEO-PBD polymersomes based on membrane fluidity, either through temperature or fluidizers, has broadly applicability in areas including targeted therapeutic delivery and synthetic biology.

  11. The Role of Membrane Fluidization in the Gel-Assisted Formation of Giant Polymersomes.

    Directory of Open Access Journals (Sweden)

    Adrienne C Greene

    Full Text Available Polymersomes are being widely explored as synthetic analogs of lipid vesicles based on their enhanced stability and potential uses in a wide variety of applications in (e.g., drug delivery, cell analogs, etc.. Controlled formation of giant polymersomes for use in membrane studies and cell mimetic systems, however, is currently limited by low-yield production methodologies. Here, we describe for the first time, how the size distribution of giant poly(ethylene glycol-poly(butadiene (PEO-PBD polymersomes formed by gel-assisted rehydration may be controlled based on membrane fluidization. We first show that the average diameter and size distribution of PEO-PBD polymersomes may be readily increased by increasing the temperature of the rehydration solution. Further, we describe a correlative relationship between polymersome size and membrane fluidization through the addition of sucrose during rehydration, enabling the formation of PEO-PBD polymersomes with a range of diameters, including giant-sized vesicles (>100 μm. This correlative relationship suggests that sucrose may function as a small molecule fluidizer during rehydration, enhancing polymer diffusivity during formation and increasing polymersome size. Overall the ability to easily regulate the size of PEO-PBD polymersomes based on membrane fluidity, either through temperature or fluidizers, has broadly applicability in areas including targeted therapeutic delivery and synthetic biology.

  12. Chitosan-glycerol phosphate/blood implants elicit hyaline cartilage repair integrated with porous subchondral bone in microdrilled rabbit defects.

    Science.gov (United States)

    Hoemann, C D; Sun, J; McKee, M D; Chevrier, A; Rossomacha, E; Rivard, G-E; Hurtig, M; Buschmann, M D

    2007-01-01

    We have previously shown that microfractured ovine defects are repaired with more hyaline cartilage when the defect is treated with in situ-solidified implants of chitosan-glycerol phosphate (chitosan-GP) mixed with autologous whole blood. The objectives of this study were (1) to characterize chitosan-GP/blood clots in vitro, and (2) to develop a rabbit marrow stimulation model in order to determine the effects of the chitosan-GP/blood implant and of debridement on the formation of incipient cartilage repair tissue. Blood clots were characterized by histology and in vitro clot retraction tests. Bilateral 3.5 x 4 mm trochlear defects debrided into the calcified layer were pierced with four microdrill holes and filled with a chitosan-GP/blood implant or allowed to bleed freely as a control. At 1 day post-surgery, initial defects were characterized by histomorphometry (n=3). After 8 weeks of repair, osteochondral repair tissues between or through the drill holes were evaluated by histology, histomorphometry, collagen type II expression, and stereology (n=16). Chitosan-GP solutions structurally stabilized the blood clots by inhibiting clot retraction. Treatment of drilled defects with chitosan-GP/blood clots led to the formation of a more integrated and hyaline repair tissue above a more porous and vascularized subchondral bone plate compared to drilling alone. Correlation analysis of repair tissue between the drill holes revealed that the absence of calcified cartilage and the presence of a porous subchondral bone plate were predictors of greater repair tissue integration with subchondral bone (Phyaline and integrated repair tissue associated with a porous subchondral bone replete with blood vessels. Concomitant regeneration of a vascularized bone plate during cartilage repair could provide progenitors, anabolic factors and nutrients that aid in the formation of hyaline cartilage.

  13. Irreversible fouling of membrane bioreactors due to formation of a non-biofilm gel layer

    DEFF Research Database (Denmark)

    Poorasgari, Eskandar; Larsen, Poul; Zheng, Xing

    2014-01-01

    Extra-cellular polymeric substances (EPS), known to contribute to fouling in membrane bio-reactors (MBRs), are generally divided into bound and free EPS. The free EPS are able to form a gel layer on the membrane active surface. The mechanisms involved in formation of such layer and its effects...... with the amount of the humic-like substances retained during filtration as predicted by gel growth theory. A low pressure backwash could re-establish the Water flux only up to 70%....

  14. Change in membrane permeability induced by protegrin 1: implication of disulphide bridges for pore formation.

    Science.gov (United States)

    Mangoni, M E; Aumelas, A; Charnet, P; Roumestand, C; Chiche, L; Despaux, E; Grassy, G; Calas, B; Chavanieu, A

    1996-03-25

    Protegrin 1 (PG-1) is a naturally occurring cationic antimicrobial peptide that is 18 residues long, has an aminated carboxy terminus and contains two disulphide bridges. Here, we investigated the antimicrobial activity of PG-1 and three linear analogues. Then, the membrane permeabilisation induced by these peptides was studied upon Xenopus laevis oocytes by electrophysiological methods. From the results obtained, we concluded that protegrin is able to form anion channels. Moreover, it seems clear that the presence of disulphide bridges is a prerequisite for the pore formation at the membrane level and not for the antimicrobial activity.

  15. Lipid Reconstitution-Enabled Formation of Gold Nanoparticle Clusters for Mimetic Cellular Membrane

    Directory of Open Access Journals (Sweden)

    Jiyoung Nam

    2016-01-01

    Full Text Available Gold nanoparticles (AuNPs encapsulated within reconstituted phospholipid bilayers have been utilized in various bioapplications due to their improved cellular uptake without compromising their advantages. Studies have proved that clustering AuNPs can enhance the efficacy of theranostic effects, but controllable aggregation or oligomerization of AuNPs within lipid membranes is still challenging. Here, we successfully demonstrate the formation of gold nanoparticle clusters (AuCLs, supported by reconstituted phospholipid bilayers with appropriate sizes for facilitating cellular uptake. Modulation of the lipid membrane curvatures influences not only the stability of the oligomeric state of the AuCLs, but also the rate of cellular uptake. Dynamic light scattering (DLS data showed that 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE, with its relatively small head group, is crucial for establishing an effective membrane curvature to encapsulate the AuCLs. The construction of phospholipid bilayers surrounding AuCLs was confirmed by analyzing the secondary structure of M2 proteins incorporated in the lipid membrane surrounding the AuCLs. When AuCLs were incubated with cells, accumulated clusters were found inside the cells without the lipids being removed or exchanged with the cellular membrane. We expect that our approach of clustering gold nanoparticles within lipid membranes can be further developed to design a versatile nanoplatform.

  16. The direct formate fuel cell with an alkaline anion exchange membrane

    Science.gov (United States)

    Bartrom, Amy M.; Haan, John L.

    2012-09-01

    We demonstrate for the first time an operating Direct Formate Fuel Cell employing formate salts as the anode fuel, air or oxygen as the oxidant, a polymer anion exchange membrane, and metal catalysts at the anode and cathode. Operation of the DFFC at 60 °C using 1 M KOOCH and 2 M KOH as the anode fuel and electrolyte and oxygen gas at the cathode produces 144 mW cm-2 of peak power density, 181 mA cm-2 current density at 0.6 V, and an open circuit voltage of 0.931 V. This performance is competitive with alkaline Direct Liquid Fuel Cells (DLFCs) previously reported in the literature and demonstrates that formate fuel is a legitimate contender with alcohol fuels for alkaline DLFCs. A survey of the literature shows that a formate-oxygen fuel cell has a high theoretical potential, and the safe, renewable formate fuel does not poison the anode catalyst.

  17. Role of transmembrane pH gradient and membrane binding in nisin pore formation.

    Science.gov (United States)

    Moll, G N; Clark, J; Chan, W C; Bycroft, B W; Roberts, G C; Konings, W N; Driessen, A J

    1997-01-01

    Nisin is a cationic antimicrobial peptide that belongs to the group of lantibiotics. It is thought to form oligomeric pores in the target membrane by a mechanism that requires the transmembrane electrical potential delta psi and that involves local pertubation of the lipid bilayer structure. Here we show that nisin does not form exclusively voltage-dependent pores: even in the absence of a delta psi, nisin is able to dissipate the transmembrane pH gradient (delta pH) in sensitive Lactococcus lactis cells and proteoliposomes. The rate of dissipation increases with the magnitude of the delta pH. Nisin forms pores only when the delta pH is inside alkaline. The efficiency of delta psi-induced pore formation is strongly affected by the external pH, whereas delta pH-induced pore formation is rather insensitive to the external pH. Nisin(1-12), an amino-terminal fragment of nisin, and (des-deltaAla5)-(nisin(1-32) amide have a strongly reduced capacity to dissipate the delta psi and delta pH in cytochrome c oxidase proteoliposomes and L. lactis cells. Both variants bind with reduced efficiency to liposomes containing negatively charged phospholipids, suggesting that both ring A and rings C to E play a role in membrane binding. Nisin(1-12) competes with nisin for membrane binding and antagonizes pore formation. These findings are consistent with the wedge model of nisin-induced pore formation.

  18. Hyalinizing trabecular tumor and papillary carcinoma of the thyroid

    Institute of Scientific and Technical Information of China (English)

    ZHU Hong; QI Ji-ping; WANG Ying-wei; SONG Yue-jia; ZHANG Zhi-yi

    2010-01-01

    Background Hyalinizing trabecular tumor (HTT) is a rare thyroid neoplasm, which shares some histologic features with thyroid papillary carcinoma (TPC). Clinically, it is frequently misdiagnosed as papillary carcinoma, even for some experienced pathologists. The aim of this study was to investigate whether HTT is variant of TPC or HTT is an independent entity of thyroid neoplasm.Methods The expression of CK19, galectin-3, HBME-1 and MIB-1 was detected by immunohistochemical staining in 12 cases of hyalinizing trabecular tumor and 20 cases of thyroid papillary carcinoma.Results Two of the 12 HTT samples were positive or focally positive for CK19. Four of the 12 samples of HTT presented positive to galectin-3; 3 were stained strongly and the other one was focally positive. None of the 12 samples of HTT was positive for HBME-1. Five in 12 HTT samples were stained in nucleus for MIB-1. Almost all the 20 cases of thyroid papillary carcinoma were intensely stained for CK19, galectin-3 and HBME-1. Fifteen in 20 cases of thyroid papillary carcinoma showed nuclear staining for MIB-1.Conclusions HTT is an independent thyroid neoplasm, not a variant of TPC. This study could help in the differential diagnosis of HTT from TPC. CK19, galectin-3 and HBME-1 are adequate to identify HTT and TPC, but MIB-1 does not play an important role in discrimination between HTT and TPC.

  19. Quasi-static elastography comparison of hyaline cartilage structures

    Energy Technology Data Exchange (ETDEWEB)

    McCredie, A J; Stride, E; Saffari, N [Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE (United Kingdom)

    2009-11-01

    Joint cartilage, a load bearing structure in mammals, has only limited ability for regeneration after damage. For tissue engineers to design functional constructs, better understanding of the properties of healthy tissue is required. Joint cartilage is a specialised structure of hyaline cartilage; a poroviscoelastic solid containing fibril matrix reinforcements. Healthy joint cartilage is layered, which is thought to be important for correct tissue function. However, the behaviour of each layer during loading is poorly understood. Ultrasound elastography provides access to depth-dependent information in real-time for a sample during loading. A 15 MHz focussed transducer provided details from scatterers within a small fixed region in each sample. Quasi-static loading was applied to cartilage samples while ultrasonic signals before and during compressions were recorded. Ultrasonic signals were processed to provide time-shift profiles using a sum-squared difference method and cross-correlation. Two structures of hyaline cartilage have been tested ultrasonically and mechanically to determine method suitability for monitoring internal deformation differences under load and the effect of the layers on the global mechanical material behaviour. Results show differences in both the global mechanical properties and the ultrasonically tested strain distributions between the two structures tested. It was concluded that these differences are caused primarily by the fibril orientations.

  20. The junction between hyaline cartilage and engineered cartilage in rabbits.

    Science.gov (United States)

    Komura, Makoto; Komura, Hiroko; Otani, Yushi; Kanamori, Yutaka; Iwanaka, Tadashi; Hoshi, Kazuto; Tsuyoshi, Takato; Tabata, Yasuhiko

    2013-06-01

    Tracheoplasty using costal cartilage grafts to enlarge the tracheal lumen was performed to treat congenital tracheal stenosis. Fibrotic granulomatous tissue was observed at the edge of grafted costal cartilage. We investigated the junction between the native hyaline cartilage and the engineered cartilage plates that were generated by auricular chondrocytes for fabricating the airway. Controlled, prospecive study. In group 1, costal cartilage from New Zealand white rabbits was collected and implanted into a space created in the cervical trachea. In group 2, chondrocytes from auricular cartilages were seeded on absorbable scaffolds. These constructs were implanted in the subcutaneous space. Engineered cartilage plates were then implanted into the trachea after 3 weeks of implantation of the constructs. The grafts in group 1 and 2 were retrieved after 4 weeks. In group 1, histological studies of the junction between the native hyaline cartilage and the implanted costal cartilage demonstrated chondrogenic tissue in four anastomoses sides out of the 10 examined. In group 2, the junction between the native trachea and the engineered cartilage showed neocartilage tissue in nine anastomoses sides out of 10. Engineered cartilage may be beneficial for engineered airways, based on the findings of the junction between the native and engineered grafts. Copyright © 2012 The American Laryngological, Rhinological and Otological Society, Inc.

  1. Reappraisal of mesenchymal chondrosarcoma: novel morphologic observations of the hyaline cartilage and endochondral ossification and beta-catenin, Sox9, and osteocalcin immunostaining of 22 cases.

    Science.gov (United States)

    Fanburg-Smith, Julie C; Auerbach, Aaron; Marwaha, Jayson S; Wang, Zengfeng; Rushing, Elisabeth J

    2010-05-01

    Mesenchymal chondrosarcoma, a rare malignant round cell and hyaline cartilage tumor, is most commonly intraosseous but can occur in extraskeletal sites. We intensively observed the morphology and applied Sox9 (master regulator of chondrogenesis), beta-catenin (involved in bone formation, thought to inhibit chondrogenesis in a Sox9-dependent manner), and osteocalcin (a marker for osteoblastic phenotype) to 22 central nervous system and musculoskeletal mesenchymal chondrosarcoma. Cases of mesenchymal chondrosarcoma were retrieved and reviewed from our files. Immunohistochemistry and follow-up were obtained on mesenchymal chondrosarcoma and tumor controls. Twenty-two mesenchymal chondrosarcomas included 5 central nervous system (all female; mean age, 30.2; mean size, 7.8 cm; in frontal lobe [n = 4] and spinal cord [n = 1]) and 17 musculoskeletal (female-male ratio, 11:6; mean age, 31.1; mean size, 6.2 cm; 3 each of humerus and vertebrae; 2 each of pelvis, rib, tibia, neck soft tissue; one each of femur, unspecified bone, and elbow soft tissue). The hyaline cartilage in most tumors revealed a consistent linear progression of chondrocyte morphology, from resting to proliferating to hypertrophic chondrocytes. Sixty-seven percent of cases demonstrated cell death and acquired osteoblastic phenotype, cells positive for osteocalcin at the site of endochondral ossification. Small round cells of mesenchymal chondrosarcoma were negative for osteocalcin. SOX9 was positive in both components of 21 of 22 cases of mesenchymal chondrosarcoma. beta-Catenin highlighted rare nuclei at the interface between round cells and hyaline cartilage in 35% cases. Control skull and central nervous system cases were compared, including chondrosarcomas and small cell osteosarcoma, the latter positive for osteocalcin in small cells. Mesenchymal chondrosarcoma demonstrates centrally located hyaline cartilage with a linear progression of chondrocytes from resting to proliferative to hypertrophic

  2. A Simple Experimental Model to Investigate Force Range for Membrane Nanotube Formation

    CERN Document Server

    Lor, Chai; Mattson-Hoss, Michelle K; Xu, Jing; Hirst, Linda S

    2016-01-01

    The presence of membrane tubules in living cells is essential to many biological processes. In cells, one mechanism to form nanosized lipid tubules is via molecular motor induced bilayer extraction. In this paper, we describe a simple experimental model to investigate the forces required for lipid tube formation using kinesin motors anchored to DOPC vesicles. Previous related studies have used molecular motors actively pulling on the membrane to extract a nanotube. Here, we invert the system geometry; molecular motors are used as static anchors linking DOPC vesicles to a two-dimensional microtubule network and an external flow is introduced to generate nanotubes facilitated by the drag force. We found that a drag force of ~7 pN was sufficient for tubule extraction for vesicles ranging from 1 to 2 um in radius. By our method, we found that the force generated by a single molecular motor was sufficient for membrane tubule extraction from a spherical lipid vesicle.

  3. Molecular Dynamics Simulations of the Permeation of Bisphenol A and Pore Formation in a Lipid Membrane

    Science.gov (United States)

    Chen, Liang; Chen, Junlang; Zhou, Guoquan; Wang, Yu; Xu, Can; Wang, Xiaogang

    2016-09-01

    Bisphenol A (BPA) is particularly considered as one of the most suspicious endocrine disruptors. Exposure to BPA may bring about possible human toxicities, such as cancerous tumors, birth defects and neoteny. One of the key issues to understand its toxicities is how BPA enters cells. In this paper, we perform molecular dynamics simulations to explore the interactions between BPA and a phospholipid membrane (dipalmitoylphosphatidylcholine, DPPC bilayer). The simulation results show that BPA can easily enter the membrane from the aqueous phase. With the increasing concentrations of BPA in the membrane, BPA tends to aggregate and form into cluster. Meanwhile, several DPPC lipids are pulled out from each leaflet and adsorbed on the cluster surface, leading to pore formation. Detailed observations indicate that the lipid extraction results mainly from the dispersion interactions between BPA cluster and lipid tails, as well as weak electrostatic attractions between lipid headgroups and the two hydroxyl groups on BPA. The lipid extraction and pore formation may cause cell membrane damage and are of great importance to uncover BPA’s cytotoxicity.

  4. Biofilm Formation on Reverse Osmosis Membranes Is Initiated and Dominated by Sphingomonas spp.▿ †

    Science.gov (United States)

    Bereschenko, L. A.; Stams, A. J. M.; Euverink, G. J. W.; van Loosdrecht, M. C. M.

    2010-01-01

    The initial formation and spatiotemporal development of microbial biofilm layers on surfaces of new and clean reverse osmosis (RO) membranes and feed-side spacers were monitored in situ using flow cells placed in parallel with the RO system of a full-scale water treatment plant. The feed water of the RO system had been treated by the sequential application of coagulation, flocculation, sand filtration, ultrafiltration, and cartridge filtration processes. The design of the flow cells permitted the production of permeate under cross-flow conditions similar to those in spiral-wound RO membrane elements of the full-scale system. Membrane autopsies were done after 4, 8, 16, and 32 days of flow-cell operation. A combination of molecular (fluorescence in situ hybridization [FISH], denaturing gradient gel electrophoresis [DGGE], and cloning) and microscopic (field emission scanning electron, epifluorescence, and confocal laser scanning microscopy) techniques was applied to analyze the abundance, composition, architecture, and three-dimensional structure of biofilm communities. The results of the study point out the unique role of Sphingomonas spp. in the initial formation and subsequent maturation of biofilms on the RO membrane and feed-side spacer surfaces. PMID:20190090

  5. Blood flow drives lumen formation by inverse membrane blebbing during angiogenesis in vivo.

    Science.gov (United States)

    Gebala, Véronique; Collins, Russell; Geudens, Ilse; Phng, Li-Kun; Gerhardt, Holger

    2016-04-01

    How vascular tubes build, maintain and adapt continuously perfused lumens to meet local metabolic needs remains poorly understood. Recent studies showed that blood flow itself plays a critical role in the remodelling of vascular networks, and suggested it is also required for the lumenization of new vascular connections. However, it is still unknown how haemodynamic forces contribute to the formation of new vascular lumens during blood vessel morphogenesis. Here we report that blood flow drives lumen expansion during sprouting angiogenesis in vivo by inducing spherical deformations of the apical membrane of endothelial cells, in a process that we have termed inverse blebbing. We show that endothelial cells react to these membrane intrusions by local and transient recruitment and contraction of actomyosin, and that this mechanism is required for single, unidirectional lumen expansion in angiogenic sprouts. Our work identifies inverse membrane blebbing as a cellular response to high external pressure. We show that in the case of blood vessels such membrane dynamics can drive local cell shape changes required for global tissue morphogenesis, shedding light on a pressure-driven mechanism of lumen formation in vertebrates.

  6. The study of membrane formation via phase inversion method by cloud point and light scattering experiment

    Science.gov (United States)

    Arahman, Nasrul; Maimun, Teuku; Mukramah, Syawaliah

    2017-01-01

    The composition of polymer solution and the methods of membrane preparation determine the solidification process of membrane. The formation of membrane structure prepared via non-solvent induced phase separation (NIPS) method is mostly determined by phase separation process between polymer, solvent, and non-solvent. This paper discusses the phase separation process of polymer solution containing Polyethersulfone (PES), N-methylpirrolidone (NMP), and surfactant Tetronic 1307 (Tet). Cloud point experiment is conducted to determine the amount of non-solvent needed on induced phase separation. Amount of water required as a non-solvent decreases by the addition of surfactant Tet. Kinetics of phase separation for such system is studied by the light scattering measurement. With the addition of Tet., the delayed phase separation is observed and the structure growth rate decreases. Moreover, the morphology of fabricated membrane from those polymer systems is analyzed by scanning electron microscopy (SEM). The images of both systems show the formation of finger-like macrovoids through the cross-section.

  7. Proline-serine-threonine phosphatase-interacting protein 2 (PSTPIP2), a host membrane-deforming protein, is critical for membranous web formation in hepatitis C virus replication.

    Science.gov (United States)

    Chao, Ti-Chun; Su, Wen-Chi; Huang, Jing-Ying; Chen, Yung-Chia; Jeng, King-Song; Wang, Horng-Dar; Lai, Michael M C

    2012-02-01

    Hepatitis C virus (HCV) reorganizes intracellular membranes to establish sites of replication. How viral and cellular proteins target, bind, and rearrange specific membranes into the replication factory remains a mystery. We used a lentivirus-based RNA interference (RNAi) screening approach to identify the potential cellular factors that are involved in HCV replication. A protein with membrane-deforming activity, proline-serine-threonine phosphatase-interacting protein 2 (PSTPIP2), was identified as a potential factor. Knockdown of PSTPIP2 in HCV subgenomic replicon-harboring and HCV-infected cells was associated with the reduction of HCV protein and RNA expression. PSTPIP2 was localized predominantly in detergent-resistant membranes (DRMs), which contain the RNA replication complex. PSTPIP2 knockdown caused a significant reduction of the formation of HCV- and NS4B-induced membranous webs. A PSTPIP2 mutant defective in inducing membrane curvature failed to support HCV replication, confirming that the membrane-deforming ability of PSTPIP2 is essential for HCV replication. Taking these results together, we suggest that PSTPIP2 facilitates membrane alterations and is a key player in the formation of the membranous web, which is the site of the HCV replication complex.

  8. Diffusion of solvent from a cast cellulose acetate solution during the formation of skinned membranes

    OpenAIRE

    Altena, F.W.; Smid, J.; Berg, van den, G.J.; Wijmans, J.G.; Smolders, C.A.

    1985-01-01

    The transport of solvent out of a cast cellulose acetate (CA) solution into the coagulation bath during membrane formation is treated as a diffusion process. From the increase of solvent concentration in the bath with time (solvent leaching experiments) an overall solvent diffusion coefficient has been calculated. In size these coefficients compare well to mutual pseudo-binary solvent-non-solvent diffusion coefficients determined by means of a classical boundary broadening method applied to t...

  9. Dynamic monitoring of membrane nanotubes formation induced by vaccinia virus on a high throughput microfluidic chip

    Science.gov (United States)

    Xiao, Min; Xu, Na; Wang, Cheng; Pang, Dai-Wen; Zhang, Zhi-Ling

    2017-03-01

    Membrane nanotubes (MNTs) are physical connections for intercellular communication and induced by various viruses. However, the formation of vaccinia virus (VACV)-induced MNTs has never been studied. In this report, VACV-induced MNTs formation process was monitored on a microfluidic chip equipped with a series of side chambers, which protected MNTs from fluidic shear stress. MNTs were formed between susceptible cells and be facilitated by VACV infection through three patterns. The formed MNTs varied with cell migration and virus concentration. The length of MNTs was positively correlated with the distance of cell migration. With increasing virus titer, the peak value of the ratio of MNT-carried cell appeared earlier. The immunofluorescence assay indicated that the rearrangement of actin fibers induced by VACV infection may lead to the formation of MNTs. This study presents evidence for the formation of MNTs induced by virus and helps us to understand the relationship between pathogens and MNTs.

  10. Building a patchwork - The yeast plasma membrane as model to study lateral domain formation.

    Science.gov (United States)

    Schuberth, Christian; Wedlich-Söldner, Roland

    2015-04-01

    The plasma membrane (PM) has to fulfill a wide range of biological functions including selective uptake of substances, signal transduction and modulation of cell polarity and cell shape. To allow efficient regulation of these processes many resident proteins and lipids of the PM are laterally segregated into different functional domains. A particularly striking example of lateral segregation has been described for the budding yeast PM, where integral membrane proteins as well as lipids exhibit very slow translational mobility and form a patchwork of many overlapping micron-sized domains. Here we discuss the molecular and physical mechanisms contributing to the formation of a multi-domain membrane and review our current understanding of yeast PM organization. Many of the fundamental principles underlying membrane self-assembly and organization identified in yeast are expected to equally hold true in other organisms, even for the more transient and elusive organization of the PM in mammalian cells. This article is part of a Special Issue entitled: Nanoscale membrane organisation and signalling.

  11. Membrane tubule formation by banana-shaped proteins with or without transient network structure

    Science.gov (United States)

    Noguchi, Hiroshi

    2016-02-01

    In living cells, membrane morphology is regulated by various proteins. Many membrane reshaping proteins contain a Bin/Amphiphysin/Rvs (BAR) domain, which consists of a banana-shaped rod. The BAR domain bends the biomembrane along the rod axis and the features of this anisotropic bending have recently been studied. Here, we report on the role of the BAR protein rods in inducing membrane tubulation, using large-scale coarse-grained simulations. We reveal that a small spontaneous side curvature perpendicular to the rod can drastically alter the tubulation dynamics at high protein density, whereas no significant difference is obtained at low density. A percolated network is intermediately formed depending on the side curvature. This network suppresses tubule protrusion, leading to the slow formation of fewer tubules. Thus, the side curvature, which is generated by protein-protein and membrane-protein interactions, plays a significant role in tubulation dynamics. We also find that positive surface tensions and the vesicle membrane curvature can stabilize this network structure by suppressing the tubulation.

  12. Structure and formation of egg membranes in Aedes aegypti. (L. ) (Diptera:Culicidae)

    Energy Technology Data Exchange (ETDEWEB)

    Mathew, G.; Rai, K.S.

    1975-01-01

    An ultrastructural study of mosquito ovarioles reveals that both the vitelline membrane and the endochorion are secreted by the follicular epithelium. The presecretory phase is characterized by the hypertrophy of endoplasmic reticulum and Golgi complex in the follicle cells. Synthesis of vitelline membrane precursors begins immediately after yolk protein uptake by micropinocytosis. Secretory droplets are budded off Golgi cisternae and released into the follicle cell--oocyte interface by exocytosis. The vitelline membrane first appears as dense plaques which eventually fuse to form a single homogeneous layer. Two types of secretory material are identified in the follicle cells prior to the formation of the endochorion. Golgi cisternae bud off small droplets similar in size and appearance to the precursors of the vitelline membrane. These migrate to the apical surface and accumulate between surface folds in the plasma membrane. The second type is a fibrous material formed in endoplasmic reticulum. When fully secreted, the endochorion is a 2-layered structure. The lower layer is comprised of pillar-like structures alternating with fibrous mesh-like areas. The pillars are formed by the coalescence of droplets released from Golgi, while the mesh-like areas presumably arise from the fibrous material. The outer layer is also fibrous. The follicle cells degenerate once the endochorion is laid down. endochorion is laid down.

  13. Lack of BRAF mutations in hyalinizing trabecular neoplasm

    Directory of Open Access Journals (Sweden)

    Brose Marcia

    2006-01-01

    Full Text Available Abstract The hyalinizing trabecular neoplasm (HTN of the thyroid is an unusual and controversial lesion. Some consider it a peculiar type of papillary thyroid carcinoma (PTC because of its nuclear features and presence of psammoma bodies. Others consider it an adenoma. Molecular studies have found RET/PTC translocations in some examples, supporting HTN as a PTC; however mutations in BRAF (another marker for PTC have not been found. We report two cases of classic HTN and a case of trabecular PTC and show BRAF mutations in the latter and not in HTN. Trabecular growth pattern is insufficient for a diagnosis of HTN and lesions with such a pattern and nuclear features of PTC are cancers. Morphologically classic HTN are not associated with metastatic potential and should be considered adenomas.

  14. Retarding of electrochemical oxidation of formate on the platinum anode by a coat of Nafion membrane

    Science.gov (United States)

    Zhang, Rui; Lv, Weixin; Li, Guanghua; Mezaal, Mohammed Adnan; Li, Xiaojing; Lei, Lixu

    2014-12-01

    It has been found that the faradaic efficiency is decreasing with the electrolysis time for electrochemical reduction of CO2 to formate on a Sn cathode with a Pt anode in an undivided electrolytic cell, because the oxidation of formed formate takes place on the Pt anode, which also limits seriously the highest concentration of formate in the system. Here, we report that a coat of Nafion membrane on the Pt anode can retard the oxidation of formate: even if the concentration of the formate in the electrolyte reaches to 0.12 mol L-1, the faradaic efficiency still maintains above 61.3%; in contrast, the oxidation reaction of the formate on the naked Pt electrode is very fast, when the concentration of the formate in the electrolyte reaches to 0.023 mol L-1, the faradaic efficiency decreases to 35.3%. This is very important because the separation of formic acid could not be economical when its concentration is not high enough, and it is also costly if the depleted solution allows too less of its concentration because the solution has to be reused in the electrochemical process.

  15. Formation of defect-free 6FDA-DAM asymmetric hollow fiber membranes for gas separations

    KAUST Repository

    Xu, Liren

    2014-06-01

    This paper reports the formation of defect-free 6FDA-DAM asymmetric hollow fiber membranes. 6FDA-polyimides are of great interest for advanced gas separation membranes, and 6FDA-DAM polyimide is a representative polymer in this family with attractive dense film properties for several potential applications. The work reported here for the 6FDA-DAM polyimide provides insight for the challenging fabrication of defect-free asymmetric hollow fiber membranes for this class of 6FDA-polyimides, which behave rather different from lower free volume polymers. Specifically, the 6FDA based materials show relatively slow phase separation rate in water quench baths, which presents a challenge for fiber spinning. For convenience, we refer to the behavior as more "non-solvent resistant" in comparison to other lower free volume polymers, since the binodal phase boundary is displaced further from the conventional position near the pure polymer-solvent axis on a ternary phase diagram in conventional polymers like Matrimid® and Ultem®. The addition of lithium nitrate to promote phase separation has a useful impact on 6FDA-DAM asymmetric hollow fiber formation. 6FDA-DAM phase diagrams using ethanol and water as non-solvent are reported, and it was found that water is less desirable as a non-solvent dope additive for defect-free fiber spinning. Phase diagrams are also reported for 6FDA-DAM dope formulation with and without the addition of lithium nitrate, and defect-free asymmetric hollow fiber membranes are reported for both cases. The effect of polymer molecular weight on defect-free fiber spinning was also investigated. Gas transport properties and morphology of hollow fibers were characterized. With several thorough case studies, this work provides a systematic guideline for defect-free fiber formation from 6FDA-polymers. © 2014 Elsevier B.V.

  16. Membraner

    DEFF Research Database (Denmark)

    Bach, Finn

    2009-01-01

    Notatet giver en kort introduktion til den statiske virkemåde af membraner og membrankonstruktioner......Notatet giver en kort introduktion til den statiske virkemåde af membraner og membrankonstruktioner...

  17. Brief report: reconstruction of joint hyaline cartilage by autologous progenitor cells derived from ear elastic cartilage.

    Science.gov (United States)

    Mizuno, Mitsuru; Kobayashi, Shinji; Takebe, Takanori; Kan, Hiroomi; Yabuki, Yuichiro; Matsuzaki, Takahisa; Yoshikawa, Hiroshi Y; Nakabayashi, Seiichiro; Ik, Lee Jeong; Maegawa, Jiro; Taniguchi, Hideki

    2014-03-01

    In healthy joints, hyaline cartilage covering the joint surfaces of bones provides cushioning due to its unique mechanical properties. However, because of its limited regenerative capacity, age- and sports-related injuries to this tissue may lead to degenerative arthropathies, prompting researchers to investigate a variety of cell sources. We recently succeeded in isolating human cartilage progenitor cells from ear elastic cartilage. Human cartilage progenitor cells have high chondrogenic and proliferative potential to form elastic cartilage with long-term tissue maintenance. However, it is unknown whether ear-derived cartilage progenitor cells can be used to reconstruct hyaline cartilage, which has different mechanical and histological properties from elastic cartilage. In our efforts to develop foundational technologies for joint hyaline cartilage repair and reconstruction, we conducted this study to obtain an answer to this question. We created an experimental canine model of knee joint cartilage damage, transplanted ear-derived autologous cartilage progenitor cells. The reconstructed cartilage was rich in proteoglycans and showed unique histological characteristics similar to joint hyaline cartilage. In addition, mechanical properties of the reconstructed tissues were higher than those of ear cartilage and equal to those of joint hyaline cartilage. This study suggested that joint hyaline cartilage was reconstructed from ear-derived cartilage progenitor cells. It also demonstrated that ear-derived cartilage progenitor cells, which can be harvested by a minimally invasive method, would be useful for reconstructing joint hyaline cartilage in patients with degenerative arthropathies.

  18. The biomechanical behaviour of the hyalinized periodontal ligament in dogs during experimental orthodontic tooth movement.

    Science.gov (United States)

    Jónsdóttir, S H; Giesen, E B W; Maltha, J C

    2012-10-01

    During orthodontic tooth movement, the mechanical behaviour of the extracellular matrix of the periodontal ligament (PDL) determines the cellular processes involved in turnover of the PDL and alveolar bone. This mechanical behaviour is the basis for finite element (FE) models and FE analyses. Five young adult male beagle dogs were used to test the null hypothesis that the mechanical behaviour of the PDL is identical in normal and hyalinized PDL. Therefore, tooth transposition was measured after standardized force application by super-elastic nickel titanium (NiTi) coil springs, exerting a constant force of 100 cN for 5 hours in both conditions. A rapid transposition during the first few seconds was found. However, it was significantly less for hyalinized than for non-hyalinized PDL. Subsequently, a short-lived creep movement was found for hyalinized PDL, while creep persisted at the non-hyalinized sides (analysis of variance and Tukey's multiple comparisons post hoc tests). The results showed substantial biomechanical differences between hyalinized and non-hyalinized PDL at different time points (Mann-Whitney). This indicates that FE models in the study of long-term orthodontic tooth movement, which are based solely on the characteristics of normal PDL should be reconsidered.

  19. WNK4 inhibits plasma membrane targeting of NCC through regulation of syntaxin13 SNARE formation.

    Science.gov (United States)

    Chung, Woo Young; Park, Hyun Woo; Han, Jung Woo; Lee, Min Goo; Kim, Joo Young

    2013-12-01

    WNK4, a serine/threonine kinase, plays a critical role in the expression of membrane proteins in the cell surface; however, the underlying mechanism of WNK4 is not clear. Here, we demonstrate that WNK4 inhibits the fusion of plasma membrane delivering vesicle with sorting/recycling endosome through disrupting SNARE formation of syntaxin13, an endosomal t-SNARE and VAMP2, the v-SNARE in plasma membrane delivering vesicle. Their interaction and co-localization were enhanced by hyperosmotic stimulation which is known for WNK4 activation. The kinase domain of WNK4 interacts with the transmembrane domain (TM) of syntaxin13 and this interaction was abolished when the TM was replaced with that of syntaxin16. Interestingly, cell fractionation using sucrose gradients revealed that WNK4 inhibited the formation of the syntaxin13/VAMP2 SNARE complex in the endosomal compartment, but not syntaxin16/VAMP2 or syntaxin13/VAMP7. Syntaxin13 was not phosphorylated by WNK4 and WNK4KI also showed the same binding strength and similar inhibitory regulation on SNARE formation of syntaxin13. Physiological relevance of this mechanism was proved with the expression of NCC (Na(+) C1(-) co-transporter) in the cell surface. The inhibiting activity of WNK4 on surface expression of NCC was abolished by syntaxin13 siRNA transfection. These results suggest that WNK4 attenuates PM targeting of NCC proteins through regulation of syntaxin13 SNARE complex formation with VAMP2 in recycling and sorting endosome. © 2013.

  20. Phosphatidylinositol 4,5-bisphosphate formation in rabbit skeletal and heart muscle membranes.

    Science.gov (United States)

    Varsányi, M; Messer, M; Brandt, N R; Heilmeyer, L M

    1986-08-14

    Incubation of rabbit skeletal muscle microsomes or isolated triads with gamma 32P-ATP/Mg2+ in the absence and in the presence of added phosphatidylinositol resulted in the formation of phosphatidylinositol 4-phosphate catalyzed by phosphatidylinositol kinase. When phosphatidylinositol 4-phosphate was added as exogenous substrate, phosphatidylinositol 4,5-bisphosphate was also formed demonstrating the presence of a membrane bound phosphatidylinositol 4-phosphate kinase. Triads were broken mechanically in a French press and separated on a continuous sucrose gradient. Incubation of these fractions with gamma 32P-ATP/Mg2+ resulted in a rapid labeling of phospholipid in a membrane fraction banding between transverse tubules and the terminal cisternae. Partial triad breakage and triad reformation experiments indicated that this phosphatidylinositol kinase was associated with T-tubules. When exogenous phosphatidylinositol 4-phosphate was employed as substrate phosphatidylinositol 4,5-bisphosphate and phosphatidic acid were formed, indicating the presence of all the enzymes of the polyphosphoinositide signaling system in this special membrane fraction. In contrast, heart muscle microsomes or plasma membranes can catalyze this reaction sequence from endogenous formed phosphatidylinositol 4-phosphate.

  1. 1. 5 MRT of the hyaline articular cartilage of the knee joint

    Energy Technology Data Exchange (ETDEWEB)

    Adam, G.; Bohndorf, K.; Krasny, R.; Guenther, R.W.; Prescher, A.

    1988-06-01

    MRI is a new method for imaging the knee joint. There is still some uncertainty regarding the extent and the signal from hyaline articular cartilage. MRI images were therefore compared with anatomical and histological preparations of the knee joint and the difference between MRI and the anatomical sections have been determined. It was shown that demonstration of hyaline cartilage was obscured by an artifact. Further investigations are required to determine the cause of this artifact and to achieve accurate imaging of hyaline cartilage by MRI.

  2. Influence of Solutocapillary Convection on Macrovoid Defect Formation in Polymeric Membranes

    Science.gov (United States)

    Pekny, M. R.; Zartman, J.; Greenberg, A. R.; Todd, P.; Krantz, W. B.

    2001-01-01

    Macrovoids (MVs) are large (10-50 micrometers) pores often found in polymeric membranes prepared via phase-inversion techniques. They are generally considered undesirable, as they adversely affect the permeability properties and performance of polymeric membranes for microfiltration, ultrafiltration, and reverse osmosis. However, MVs can be useful in certain thin-film applications in which vapor transmission is necessary, or for use as reservoirs for enzymes or liquid membrane material. If more could be learned about the nature and causes of MV formation, it might be possible to devise techniques to control and/or prevent MV formation that are more effective than those currently employed. Two hypotheses for the MV growth mechanism have been advanced. Reuvers proposed that once initiated, MV growth can be attributed to diffusion of (primarily) solvent to the MV nuclei. Because this mechanism does not involve gross movement of the MV, the presence or absence of body forces such as buoyancy should not significantly affect MV growth. On the other hand, Shojaie et al. proposed that solutocapillary convection induced by a steep surface-tension gradient along the MV/bulk solution interface enhances mass transfer to the growing MV. This interfacial convection exerts a force that pulls the growing MV downward into the casting solution. Both buoyancy and viscous drag hinder MV growth by inhibiting this motion. Thus, removing the buoyancy force by casting in microgravity should augment MV growth according to this hypothesis. Whereas neither surface tension nor gravity has a significant effect on MV growth according to the first hypothesis, buoyancy forces should be important if the second hypothesis is correct. The overall goal of this research is to test these two hypotheses in order to improve our understanding of the MV growth processing solvent-cast polymeric membranes. Studying MV growth in low-gravity conditions is pivotal to our ability to discriminate between these

  3. Increased Outer Membrane Vesicle Formation in a Helicobacter pylori tolB Mutant.

    Science.gov (United States)

    Turner, Lorinda; Praszkier, Judyta; Hutton, Melanie L; Steer, David; Ramm, Georg; Kaparakis-Liaskos, Maria; Ferrero, Richard L

    2015-08-01

    Multiple studies have established the importance of the tol-pal gene cluster in bacterial cell membrane integrity and outer membrane vesicle (OMV) formation in Escherichia coli. In contrast, the functions of Tol-Pal proteins in pathogenic organisms, including those of the Epsilonproteobacteria, remain poorly if at all defined. The aim of this study was to characterize the roles of two key components of the Tol-Pal system, TolB and Pal, in OMV formation in the pathogenic bacterium, Helicobacter pylori. H. pylori ΔtolB, Δpal and ΔtolBpal mutants, as well as complemented strains, were generated and assessed for changes in morphology and OMV production by scanning electron microscopy and enzyme-linked immunoassay (ELISA), respectively. The protein content and pro-inflammatory properties of OMVs were determined by mass spectroscopy and interleukin-8 (IL-8) ELISA on culture supernatants from OMV-stimulated cells, respectively. H. pylori ΔtolB and Δpal bacteria exhibited aberrant cell morphology and/or flagella biosynthesis. Importantly, the disruption of H. pylori tolB but not pal resulted in a significant increase in OMV production. The OMVs from H. pylori ΔtolB and Δpal bacteria harbored many of the major outer membrane and virulence proteins observed in wild-type (WT) OMVs. Interestingly, ΔtolB, Δpal and ΔtolBpal OMVs induced significantly higher levels of IL-8 production by host cells, compared with WT OMVs. This work demonstrates that TolB and Pal are important for membrane integrity in H. pylori. Moreover, it shows how H. pylori tolB-pal genes may be manipulated to develop "hypervesiculating" strains for vaccine purposes. © 2015 John Wiley & Sons Ltd.

  4. Structural determinants for membrane insertion, pore formation and translocation of Clostridium difficile toxin B.

    Science.gov (United States)

    Genisyuerek, Selda; Papatheodorou, Panagiotis; Guttenberg, Gregor; Schubert, Rolf; Benz, Roland; Aktories, Klaus

    2011-03-01

    Clostridium difficile toxins A and B bind to eukaryotic target cells, are endocytosed and then deliver their N-terminal glucosyltransferase domain after processing into the cytosol. Whereas glucosyltransferase, autoprocessing and cell-binding domains are well defined, structural features involved in toxin delivery are unknown. Here, we studied structural determinants that define membrane insertion, pore formation and translocation of toxin B. Deletion analyses revealed that a large region, covering amino acids 1501-1753 of toxin B, is dispensable for cytotoxicity in Vero cells. Accordingly, a chimeric toxin, consisting of amino acids 1-1550 and the receptor-binding domain of diphtheria toxin, caused cytotoxic effects. A large N-terminal part of toxin B (amino acids 1-829) was not essential for pore formation (measured by (86) Rb(+) release in mammalian cells). Studies using C-terminal truncation fragments of toxin B showed that amino acid residues 1-990 were still capable of inducing fluorescence dye release from large lipid vesicles and led to increased electrical conductance in black lipid membranes. Thereby, we define the minimal pore-forming region of toxin B within amino acid residues 830 and 990. Moreover, we identify within this region a crucial role of the amino acid pair glutamate-970 and glutamate-976 in pore formation of toxin B.

  5. A rapid, membrane-dependent pathway directs furrow formation through RalA in the early Drosophila embryo.

    Science.gov (United States)

    Holly, Ryan M; Mavor, Lauren M; Zuo, Zhongyuan; Blankenship, J Todd

    2015-07-01

    Plasma membrane furrow formation is crucial in cell division and cytokinesis. Furrow formation in early syncytial Drosophila embryos is exceptionally rapid, with furrows forming in as little as 3.75 min. Here, we use 4D imaging to identify furrow formation, stabilization, and regression periods, and identify a rapid, membrane-dependent pathway that is essential for plasma membrane furrow formation in vivo. Myosin II function is thought to provide the ingression force for cytokinetic furrows, but the role of membrane trafficking pathways in guiding furrow formation is less clear. We demonstrate that a membrane trafficking pathway centered on Ras-like protein A (RalA) is required for fast furrow ingression in the early fly embryo. RalA function is absolutely required for furrow formation and initiation. In the absence of RalA and furrow function, chromosomal segregation is aberrant and polyploid nuclei are observed. RalA localizes to syncytial furrows, and mediates the movement of exocytic vesicles to the plasma membrane. Sec5, which is an exocyst complex subunit and localizes to ingressing furrows in wild-type embryos, becomes punctate and loses its cortical association in the absence of RalA function. Rab8 also fails to traffic to the plasma membrane and accumulates aberrantly in the cytoplasm in RalA disrupted embryos. RalA localization precedes F-actin recruitment to the furrow tip, suggesting that membrane trafficking might function upstream of cytoskeletal remodeling. These studies identify a pathway, which stretches from Rab8 to RalA and the exocyst complex, that mediates rapid furrow formation in early Drosophila embryos.

  6. Monte Carlo study of receptor-lipid raft formation on a cell membrane

    Science.gov (United States)

    Yu-Yang, Paul; Srinivas Reddy, A.; Raychaudhuri, Subhadip

    2012-02-01

    Receptors are cell surface molecules that bind with extracellular ligand molecules leading to propagation of downstream signals and cellular activation. Even though ligand binding-induced formation of receptor-lipid rafts has been implicated in such a process, the formation mechanism of such large stable rafts is not understood. We present findings from our Monte Carlo (MC) simulations involving (i) receptor interaction with the membrane lipids and (ii) lipid-lipid interactions between raft forming lipids. We have developed a hybrid MC simulation method that combines a probabilistic MC simulation with an explicit free energy-based MC scheme. Some of the lipid-mediated interactions, such as the cholesterol-lipid interactions, are simulated in an implicit way. We examine the effect of varying attractive interactions between raft forming lipids and ligand-bound receptors and show that strong coupling between receptor-receptor and receptor-sphingolipid molecules generate raft formation similar to that observed in recent biological experiments. We study the effect of variation of receptor affinity for ligands (as happens in adaptive immune cells) on raft formation. Such affinity dependence in receptor-lipid raft formation provides insight into important problems in B cell biology.

  7. Sonication-induced Ostwald ripening of ZIF-8 nanoparticles and formation of ZIF-8/polymer composite membranes

    KAUST Repository

    Thompson, Joshua A.

    2012-08-01

    The effect of typical membrane processing conditions on the structure, interfacial morphology, and gas separation performance of MOF/polymer nanocomposite membranes is investigated. In particular, the ZIF-8/Matrimid® nanocomposite membrane system is examined, and it is shown that ultrasonication - a commonly employed particle dispersion method - induces significant changes in the shape, size distribution, and structure of ZIF-8 particles suspended in an organic solvent during membrane processing. Dynamic light scattering and electron microscopy reveal that ZIF-8 nanoparticles undergo substantial Ostwald ripening when subjected to high intensity ultrasonication as often required in the formation of MOF/polymer nanocomposite membranes. Other characterization techniques reveal that the ripened particles exhibit lower pore volumes and lower surface areas compared to the as-made material. ZIF-8/Matrimid® composite membranes fabricated using two sonication methods show significant differences in microstructure. Permeation measurements show significant enhancement in permeability of CO 2 and increased CO 2/CH 4 selectivity in membranes fabricated with high-intensity sonication. In contrast, composite membranes prepared with low-intensity sonication are found to be defective. A careful evaluation of MOF membrane processing conditions, as well as knowledge of the properties of the MOF material after these membrane processing steps, are necessary to develop reliable processing-structure-property relations for MOF-containing membranes. © 2012 Elsevier Inc. All rights reserved.

  8. Microbial adhesion and biofilm formation on microfiltration membranes: a detailed characterization using model organisms with increasing complexity.

    Science.gov (United States)

    Vanysacker, L; Denis, C; Declerck, P; Piasecka, A; Vankelecom, I F J

    2013-01-01

    Since many years, membrane biofouling has been described as the Achilles heel of membrane fouling. In the present study, an ecological assay was performed using model systems with increasing complexity: a monospecies assay using Pseudomonas aeruginosa or Escherichia coli separately, a duospecies assay using both microorganisms, and a multispecies assay using activated sludge with or without spiked P. aeruginosa. The microbial adhesion and biofilm formation were evaluated in terms of bacterial cell densities, species richness, and bacterial community composition on polyvinyldifluoride, polyethylene, and polysulfone membranes. The data show that biofouling formation was strongly influenced by the kind of microorganism, the interactions between the organisms, and the changes in environmental conditions whereas the membrane effect was less important. The findings obtained in this study suggest that more knowledge in species composition and microbial interactions is needed in order to understand the complex biofouling process. This is the first report describing the microbial interactions with a membrane during the biofouling development.

  9. Joint immobilization inhibits spontaneous hyaline cartilage regeneration induced by a novel double-network gel implantation.

    Science.gov (United States)

    Arakaki, Kazunobu; Kitamura, Nobuto; Kurokawa, Takayuki; Onodera, Shin; Kanaya, Fuminori; Gong, Jian-Ping; Yasuda, Kazunori

    2011-02-01

    We have recently discovered that spontaneous hyaline cartilage regeneration can be induced in an osteochondral defect in the rabbit, when we implant a novel double-network (DN) gel plug at the bottom of the defect. To clarify whether joint immobilization inhibits the spontaneous hyaline cartilage regeneration, we conducted this study with 20 rabbits. At 4 or 12 weeks after surgery, the defect in the mobile knees was filled with a sufficient volume of the hyaline cartilage tissue rich in proteoglycan and type-2 collagen, while no cartilage tissues were observed in the defect in the immobilized knees. Type-2 collagen, Aggrecan, and SOX9 mRNAs were expressed only in the mobile knees at each period. This study demonstrated that joint immobilization significantly inhibits the spontaneous hyaline cartilage regeneration induced by the DN gel implantation. This fact suggested that the mechanical environment is one of the significant factors to induce this phenomenon.

  10. Enhancing the formation and shear resistance of nitrifying biofilms on membranes by surface modification

    DEFF Research Database (Denmark)

    Lackner, Susanne; Holmberg, Maria; Terada, Akihiko;

    2009-01-01

    Polypropylene (PP) membranes and polyethylene (PE) surfaces were modified to enhance formation and shear resistance of nitrifying biofilms for wastewater treatment applications. A combination of plasma polymerization and wet chemistry was employed to ultimately introduce poly(ethyleneglycol) (PEG...... similar trends: biofilms on -PEG-NH2 modified surfaces were much stronger compared to the other modifications and the unmodified reference surfaces. Electrostatic interactions between the protonated amino group and negatively charged bacteria as well as PEG chain density which can affect the surface...... structure might be possible explanations of the superiority of the -PEG-NH2 modification. The success of the-PEG-NH2 modification was independent of the original surface and might, therefore, be used in wastewater treatment bioreactors to improve reactor performance by making biofilm formation more stable...

  11. Physical mechanisms of micro- and nanodomain formation in multicomponent lipid membranes

    CERN Document Server

    Schmid, Friederike

    2016-01-01

    This article summarizes a variety of physical mechanisms proposed in the literature, which can generate micro- and nanodomains in multicomponent lipid bilayers and biomembranes. It mainly focusses on lipid-driven mechanisms that do not involve direct protein-protein interactions. Specifically, it considers (i) equilibrium mechanisms based on lipid-lipid phase separation such as critical cluster formation close to critical points, and multiple domain formation in curved geometries, (ii) equilibrium mechanisms that stabilize two-dimensional microemulsions, such as the effect of linactants and the effect of curvature-composition coupling in bilayers and monolayers, and (iii) non-equilibrium mechanisms induced by the interaction of a biomembrane with the cellular environment, such as membrane recycling and the pinning effects of the cytoplasm. Theoretical predictions are discussed together with simulations and experiments. The presentation is guided by the theory of phase transitions and critical phenomena, and t...

  12. Regeneration of hyaline cartilage promoted by xenogeneic mesenchymal stromal cells embedded within elastin-like recombinamer-based bioactive hydrogels.

    Science.gov (United States)

    Pescador, David; Ibáñez-Fonseca, Arturo; Sánchez-Guijo, Fermín; Briñón, Jesús G; Arias, Francisco Javier; Muntión, Sandra; Hernández, Cristina; Girotti, Alessandra; Alonso, Matilde; Del Cañizo, María Consuelo; Rodríguez-Cabello, José Carlos; Blanco, Juan Francisco

    2017-08-01

    Over the last decades, novel therapeutic tools for osteochondral regeneration have arisen from the combination of mesenchymal stromal cells (MSCs) and highly specialized smart biomaterials, such as hydrogel-forming elastin-like recombinamers (ELRs), which could serve as cell-carriers. Herein, we evaluate the delivery of xenogeneic human MSCs (hMSCs) within an injectable ELR-based hydrogel carrier for osteochondral regeneration in rabbits. First, a critical-size osteochondral defect was created in the femora of the animals and subsequently filled with the ELR-based hydrogel alone or with embedded hMSCs. Regeneration outcomes were evaluated after three months by gross assessment, magnetic resonance imaging and computed tomography, showing complete filling of the defect and the de novo formation of hyaline-like cartilage and subchondral bone in the hMSC-treated knees. Furthermore, histological sectioning and staining of every sample confirmed regeneration of the full cartilage thickness and early subchondral bone repair, which was more similar to the native cartilage in the case of the cell-loaded ELR-based hydrogel. Overall histological differences between the two groups were assessed semi-quantitatively using the Wakitani scale and found to be statistically significant (p hyaline cartilage in osteochondral lesions.

  13. Platelet-rich plasma loaded in situ-formed hydrogel enhances hyaline cartilage regeneration by CB1 upregulation.

    Science.gov (United States)

    Lee, Hye-Rim; Park, Kyung Min; Joung, Yoon Ki; Park, Ki Dong; Do, Sun Hee

    2012-11-01

    The efficacy of three-dimensional (3D) culture on the proliferation and maturation of chondrocytes seeded into a hydrogel scaffold was assessed. Three types of hydrogel were prepared for the 3D culture of primary isolated chondrocytes. Chondrocyte proliferation was assessed using a live/dead viability/cytotoxicity assay and semiquantitative RT-PCR after 3D culture in hydrogel. Cylindrical defects in the center of rat xyphoids were used for the implantation of platelet-rich plasma (PRP)/hydrogel composites. Rats were killed at day 7 postoperatively and evaluated histochemically and immunohistologically. Xyphoid chondrocytes proliferated well with time in hydrogels. In the PRP-containing hydrogels, xyphoid defects displayed early formation of chondroid matrix with massive peripheral infiltration of spindle cells. These results were consistent with Safranin-O staining for proteoglycans and immunohistochemistry for type II collagen. Gene expression analyses in vitro revealed aggrecan, type II collagen, and ChM-1 and CB1 upregulation by PRP/hydrogel. PRP/hydrogel provided a suitable environment for hyaline cartilaginous regeneration, leading to anti-inflammation by significant increase of CB1 and inhibiting vascular ingrowth via considerable upregulation of ChM-1. The results provide a valuable reference for the clinical application of hydrogel scaffolds for hyaline cartilage regeneration, as well as the use of autologous PRP to improve cellular proliferation and maturation of xyphoid repair. Copyright © 2012 Wiley Periodicals, Inc.

  14. Positive effects of cell-free porous PLGA implants and early loading exercise on hyaline cartilage regeneration in rabbits.

    Science.gov (United States)

    Chang, Nai-Jen; Lin, Chih-Chan; Shie, Ming-You; Yeh, Ming-Long; Li, Chien-Feng; Liang, Peir-In; Lee, Kuan-Wei; Shen, Pei-Hsun; Chu, Chih-Jou

    2015-12-01

    The regeneration of hyaline cartilage remains clinically challenging. Here, we evaluated the therapeutic effects of using cell-free porous poly(lactic-co-glycolic acid) (PLGA) graft implants (PGIs) along with early loading exercise to repair a full-thickness osteochondral defect. Rabbits were randomly allocated to a treadmill exercise (TRE) group or a sedentary (SED) group and were prepared as either a PGI model or an empty defect (ED) model. TRE was performed as a short-term loading exercise; SED was physical inactivity in a free cage. The knees were evaluated at 6 and 12 weeks after surgery. At the end of testing, none of the knees developed synovitis, formed osteophytes, or became infected. Macroscopically, the PGI-TRE group regenerated a smooth articular surface, with transparent new hyaline-like tissue soundly integrated with the neighboring cartilage, but the other groups remained distinct at the margins with fibrous or opaque tissues. In a micro-CT analysis, the synthesized bone volume/tissue volume (BV/TV) was significantly higher in the PGI-TRE group, which also had integrating architecture in the regeneration site. The thickness of the trabecular (subchondral) bone was improved in all groups from 6 to 12 weeks. Histologically, remarkable differences in the cartilage regeneration were visible. At week 6, compared with SED groups, the TRE groups manifested modest inflammatory cells with pro-inflammatory cytokines (i.e., TNF-α and IL-6), improved collagen alignment and higher glycosaminoglycan (GAG) content, particularly in the PGI-TRE group. At week 12, the PGI-TRE group had the best regeneration outcomes, showing the formation of hyaline-like cartilage, the development of columnar rounded chondrocytes that expressed enriched levels of collagen type II and GAG, and functionalized trabecular bone with osteocytes. In summary, the combination of implanting cell-free PLGA and performing an early loading exercise can significantly promote the full

  15. A conserved cysteine residue is involved in disulfide bond formation between plant plasma membrane aquaporin monomers.

    Science.gov (United States)

    Bienert, Gerd P; Cavez, Damien; Besserer, Arnaud; Berny, Marie C; Gilis, Dimitri; Rooman, Marianne; Chaumont, François

    2012-07-01

    AQPs (aquaporins) are conserved in all kingdoms of life and facilitate the rapid diffusion of water and/or other small solutes across cell membranes. Among the different plant AQPs, PIPs (plasma membrane intrinsic proteins), which fall into two phylogenetic groups, PIP1 and PIP2, play key roles in plant water transport processes. PIPs form tetramers in which each monomer acts as a functional channel. The intermolecular interactions that stabilize PIP oligomer complexes and are responsible for the resistance of PIP dimers to denaturating conditions are not well characterized. In the present study, we identified a highly conserved cysteine residue in loop A of PIP1 and PIP2 proteins and demonstrated by mutagenesis that it is involved in the formation of a disulfide bond between two monomers. Although this cysteine seems not to be involved in regulation of trafficking to the plasma membrane, activity, substrate selectivity or oxidative gating of ZmPIP1s (Zm is Zea mays), ZmPIP2s and hetero-oligomers, it increases oligomer stability under denaturating conditions. In addition, when PIP1 and PIP2 are co-expressed, the loop A cysteine of ZmPIP1;2, but not that of ZmPIP2;5, is involved in the mercury sensitivity of the channels.

  16. A Simple Experimental Model to Investigate Force Range for Membrane Nanotube Formation

    Directory of Open Access Journals (Sweden)

    Chai eLor

    2016-02-01

    Full Text Available The presence of membrane tubules in living cells is essential to many biological processes. In cells, one mechanism to form nano-sized lipid tubules is via molecular motor induced bilayer extraction. In this paper, we describe a simple experimental model to investigate the forces required for lipid tube formation using kinesin motors anchored to 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC vesicles. Previous related studies have used molecular motors actively pulling on the membrane to extract a nanotube. Here we invert the system geometry; molecular motors are used as static anchors linking DOPC vesicles to a two-dimensional microtubule network, and an external flow is introduced to generate nanotubes facilitated by the drag force. We find that a drag force of approximately ≈7 pN is sufficient for tubule extraction for vesicles ranging from 1-2 um in radius. By our method, we find that the force generated by a single molecular motor is sufficient for membrane tubule extraction from a spherical lipid vesicle.

  17. Outer Membrane Vesicles of Helicobacter pylori TK1402 are Involved in Biofilm Formation

    Directory of Open Access Journals (Sweden)

    Ochiai Kuniyasu

    2009-09-01

    Full Text Available Abstract Background Helicobacter pylori forms biofilms on glass surfaces at the air-liquid interface in in vitro batch cultures; however, biofilms of H. pylori have not been well characterized. In the present study, we analyzed the ability of H. pylori strains to form biofilms and characterized the underlying mechanisms of H. pylori biofilm formation. Results Strain TK1402 showed strong biofilm forming ability relative to the other strains in Brucella broth supplemented with 7% FCS. The strong biofilm forming ability of TK1402 is reflected the relative thickness of the biofilms. In addition, outer membrane vesicles (OMV were detected within the matrix of only the TK1402 biofilms. Biofilm formation was strongly correlated with the production of OMV in this strain. We further observed that strain TK1402 did not form thick biofilms in Brucella broth supplemented with 0.2% β-cyclodextrin. However, the addition of the OMV-fraction collected from TK1402 could enhance biofilm formation. Conclusion The results suggested that OMV produced from TK1402 play an important role in biofilm formation in strain TK1402.

  18. Urotensin II receptor (UTR) exists in hyaline chondrocytes: a study of peripheral distribution of UTR in the African clawed frog, Xenopus laevis.

    Science.gov (United States)

    Konno, Norifumi; Fujii, Yuya; Imae, Haruka; Kaiya, Hiroyuki; Mukuda, Takao; Miyazato, Mikiya; Matsuda, Kouhei; Uchiyama, Minoru

    2013-05-01

    Urotensin II (UII) and UII-related peptide (URP) exhibit diverse physiological actions including vasoconstriction, locomotor activity, osmoregulation, and immune response through UII receptor (UTR), which is expressed in the central nervous system and peripheral tissues of fish and mammals. In amphibians, only UII has been identified. As the first step toward elucidating the actions of UII and URP in amphibians, we cloned and characterized URP and UTR from the African clawed frog Xenopus laevis. Functional analysis showed that treatment of UII or URP with Chinese hamster ovary cells transfected with the cloned receptor increased the intracellular calcium concentration in a concentration-dependent manner, whereas the administration of the UTR antagonist urantide inhibited UII- or URP-induced Ca(2+) mobilization. An immunohistochemical study showed that UTR was expressed in the splenocytes and leukocytes isolated from peripheral blood, suggesting that UII and URP are involved in the regulation of the immune system. UTR was also localized in the apical membrane of the distal tubule of the kidney and in the transitional epithelial cells of the urinary bladder. This result supports the view that the UII/URP-UTR system plays an important role in osmoregulation of amphibians. Interestingly, immunopositive labeling for UTR was first detected in the chondrocytes of various hyaline cartilages (the lung septa, interphalangeal joint and sternum). The expression of UTR was also observed in the costal cartilage, tracheal cartilages, and xiphoid process of the rat. These novel findings probably suggest that UII and URP mediate the formation of the cartilaginous matrix. Copyright © 2013 Elsevier Inc. All rights reserved.

  19. In situ formation of silver nanoparticles on thin-film composite reverse osmosis membranes for biofouling mitigation.

    Science.gov (United States)

    Ben-Sasson, Moshe; Lu, Xinglin; Bar-Zeev, Edo; Zodrow, Katherine R; Nejati, Siamak; Qi, Genggeng; Giannelis, Emmanuel P; Elimelech, Menachem

    2014-10-01

    The potential to incorporate silver nanoparticles (Ag-NPs) as biocides in membranes for water purification has gained much interest in recent years. However, a viable strategy for loading the Ag-NPs on the membrane remains challenging. This paper presents a novel, facile procedure for loading Ag-NPs on thin-film composite (TFC) reverse osmosis membranes. Reaction of silver salt with a reducing agent on the membrane surface resulted in uniform coverage of Ag-NPs, irreversibly bound to the membrane, as confirmed by XPS, TEM, and SEM analyses. Salt selectivity of the membrane as well its surface roughness, hydrophilicity, and zeta potential were not impacted by Ag-NP functionalization, while a slight reduction (up to 17%) in water permeability was observed. The formed Ag-NPs imparted strong antibacterial activity to the membrane, leading to reduction of more than 75% in the number of live bacteria attached to the membrane for three model bacteria strains. In addition, confocal microscopy analyses revealed that Ag-NPs significantly suppressed biofilm formation, with 41% reduction in total biovolume and significant reduction in EPS, dead, and live bacteria on the functionalized membrane. The simplicity of the method, the short reaction time, the ability to load the Ag-NPs on site, and the strong imparted antibacterial activity highlight the potential of this method in real-world RO membrane applications. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. In situ formation of silver nanoparticles on thin-film composite reverse osmosis membranes for biofouling mitigation

    KAUST Repository

    Ben-Sasson, Moshe

    2014-10-01

    The potential to incorporate silver nanoparticles (Ag-NPs) as biocides in membranes for water purification has gained much interest in recent years. However, a viable strategy for loading the Ag-NPs on the membrane remains challenging. This paper presents a novel, facile procedure for loading Ag-NPs on thin-film composite (TFC) reverse osmosis membranes. Reaction of silver salt with a reducing agent on the membrane surface resulted in uniform coverage of Ag-NPs, irreversibly bound to the membrane, as confirmed by XPS, TEM, and SEM analyses. Salt selectivity of the membrane as well its surface roughness, hydrophilicity, and zeta potential were not impacted by Ag-NP functionalization, while a slight reduction (up to 17%) in water permeability was observed. The formed Ag-NPs imparted strong antibacterial activity to the membrane, leading to reduction of more than 75% in the number of live bacteria attached to the membrane for three model bacteria strains. In addition, confocal microscopy analyses revealed that Ag-NPs significantly suppressed biofilm formation, with 41% reduction in total biovolume and significant reduction in EPS, dead, and live bacteria on the functionalized membrane. The simplicity of the method, the short reaction time, the ability to load the Ag-NPs on site, and the strong imparted antibacterial activity highlight the potential of this method in real-world RO membrane applications. © 2014 Elsevier Ltd.

  1. Adipose stem cells can secrete angiogenic factors that inhibit hyaline cartilage regeneration.

    Science.gov (United States)

    Lee, Christopher Sd; Burnsed, Olivia A; Raghuram, Vineeth; Kalisvaart, Jonathan; Boyan, Barbara D; Schwartz, Zvi

    2012-08-24

    Adipose stem cells (ASCs) secrete many trophic factors that can stimulate tissue repair, including angiogenic factors, but little is known about how ASCs and their secreted factors influence cartilage regeneration. Therefore, the aim of this study was to determine the effects ASC-secreted factors have in repairing chondral defects. ASCs isolated from male Sprague Dawley rats were cultured in monolayer or alginate microbeads supplemented with growth (GM) or chondrogenic medium (CM). Subsequent co-culture, conditioned media, and in vivo cartilage defect studies were performed. ASC monolayers and microbeads cultured in CM had decreased FGF-2 gene expression and VEGF-A secretion compared to ASCs cultured in GM. Chondrocytes co-cultured with GM-cultured ASCs for 7 days had decreased mRNAs for col2, comp, and runx2. Chondrocytes treated for 12 or 24 hours with conditioned medium from GM-cultured ASCs had reduced sox9, acan, and col2 mRNAs; reduced proliferation and proteoglycan synthesis; and increased apoptosis. ASC-conditioned medium also increased endothelial cell tube lengthening whereas conditioned medium from CM-cultured ASCs had no effect. Treating ASCs with CM reduced or abolished these deleterious effects while adding a neutralizing antibody for VEGF-A eliminated ASC-conditioned medium induced chondrocyte apoptosis and restored proteoglycan synthesis. FGF-2 also mitigated the deleterious effects VEGF-A had on chondrocyte apoptosis and phenotype. When GM-grown ASC pellets were implanted in 1 mm non-critical hyaline cartilage defects in vivo, cartilage regeneration was inhibited as evaluated by radiographic and equilibrium partitioning of an ionic contrast agent via microCT imaging. Histology revealed that defects with GM-cultured ASCs had no tissue ingrowth from the edges of the defect whereas empty defects and defects with CM-grown ASCs had similar amounts of neocartilage formation. ASCs must be treated to reduce the secretion of VEGF-A and other factors that

  2. Enhancing the formation and shear resistance of nitrifying biofilms on membranes by surface modification.

    Science.gov (United States)

    Lackner, Susanne; Holmberg, Maria; Terada, Akihiko; Kingshott, Peter; Smets, Barth F

    2009-08-01

    Polypropylene (PP) membranes and polyethylene (PE) surfaces were modified to enhance formation and shear resistance of nitrifying biofilms for wastewater treatment applications. A combination of plasma polymerization and wet chemistry was employed to ultimately introduce poly(ethyleneglycol) (PEG) chains with two different functional groups (-PEG-NH(2) and -PEG-CH(3)). Biofilm growth experiments using a mixed nitrifying bacterial culture revealed that the specific combination of PEG chains with amino groups resulted in most biofilm formation on both PP and PE samples. Detachment experiments showed similar trends: biofilms on -PEG-NH(2) modified surfaces were much stronger compared to the other modifications and the unmodified reference surfaces. Electrostatic interactions between the protonated amino group and negatively charged bacteria as well as PEG chain density which can affect the surface structure might be possible explanations of the superiority of the -PEG-NH(2) modification. The success of the-PEG-NH(2) modification was independent of the original surface and might, therefore, be used in wastewater treatment bioreactors to improve reactor performance by making biofilm formation more stable and predictable.

  3. Time Resolved Neutron Reflectivity During Supported Membrane Formation by Vesicle Fusion.

    Science.gov (United States)

    Koutsioubas, Alexandros; Appavou, Marie-Sousai; Lairez, Didier

    2017-09-05

    The formation of supported lipid bilayers (SLB) on hydrophilic substrates through the method of unilamelar vesicle fusion is used routinely in a wide range of biophysical studies. In an effort to control and better understand the fusion process on the substrate, many experimental studies employing different techniques have been devoted to the elucidation of the fusion mechanism. In the present work we follow the kinetics of membrane formation using time-resolved (TR) neutron reflectivity, focussing at the structural changes near the solid/liquid interface. A clear indication of stacked bilayer structure is observed during the intermediate phase of SLB formation. Adsorbed lipid mass decrease is also measured at the final stage of the process. We have found that it is essential for the analysis of the experimental results to treat theoretically the shape of adsorbed lipid vesicles on an attractive substrate. The overall findings are discussed in relation to proposed fusion mechanisms from previous literature, while we argue that our observations favour a model involving enhanced adhesion of incoming vesicles on the edges of already formed bilayer patches.

  4. Oncogenic Mutations Differentially Affect Bax Monomer, Dimer, and Oligomeric Pore Formation in the Membrane

    Science.gov (United States)

    Zhang, Mingzhen; Zheng, Jie; Nussinov, Ruth; Ma, Buyong

    2016-09-01

    Dysfunction of Bax, a pro-apoptotic regulator of cellular metabolism is implicated in neurodegenerative diseases and cancer. We have constructed the first atomistic models of the Bax oligomeric pore consisting with experimental residue-residue distances. The models are stable, capturing well double electron-electron resonance (DEER) spectroscopy measurements and provide structural details in line with the DEER data. Comparison with the latest experimental results revealed that our models agree well with both Bax and Bak pores, pointed to a converged structural arrangement for Bax and Bak pore formation. Using multi-scale molecular dynamics simulations, we probed mutational effects on Bax transformation from monomer → dimer → membrane pore formation at atomic resolution. We observe that two cancer-related mutations, G40E and S118I, allosterically destabilize the monomer and stabilize an off-pathway swapped dimer, preventing productive pore formation. This observation suggests a mechanism whereby the mutations may work mainly by over-stabilizing the monomer → dimer transformation toward an unproductive off-pathway swapped-dimer state. Our observations point to misfolded Bax states, shedding light on the molecular mechanism of Bax mutation-elicited cancer. Most importantly, the structure of the Bax pore facilitates future study of releases cytochrome C in atomic detail.

  5. Time-resolved GISAXS and cryo-microscopy characterization of block copolymer membrane formation

    KAUST Repository

    Marques, Debora S.

    2014-03-01

    Time-resolved grazing-incidence small-angle X-ray scattering (GISAXS) and cryo-microscopy were used for the first time to understand the pore evolution by copolymer assembly, leading to the formation of isoporous membranes with exceptional porosity and regularity. The formation of copolymer micelle strings in solution (in DMF/DOX/THF and DMF/DOX) was confirmed by cryo field emission scanning electron microscopy (cryo-FESEM) with a distance of 72 nm between centers of micelles placed in different strings. SAXS measurement of block copolymer solutions in DMF/DOX indicated hexagonal assembly with micelle-to-micelle distance of 84-87 nm for 14-20 wt% copolymer solutions. GISAXS in-plane peaks were detected, revealing order close to hexagonal. The d-spacing corresponding to the first peak in this case was 100-130 nm (lattice constant 115-150 nm) for 17 wt% copolymer solutions evaporating up to 100 s. Time-resolved cryo-FESEM showed the formation of incipient pores on the film surface after 4 s copolymer solution casting with distances between void centers of 125 nm. © 2014 Elsevier Ltd. All rights reserved.

  6. Study of differential properties of fibrochondrocytes and hyaline chondrocytes in growing rabbits.

    Science.gov (United States)

    Huang, L; Li, M; Li, H; Yang, C; Cai, X

    2015-02-01

    We aimed to build a culture model of chondrocytes in vitro, and to study the differential properties between fibrochondrocytes and hyaline chondrocytes. Histological sections were stained with haematoxylin and eosin so that we could analyse the histological structure of the fibrocartilage and hyaline cartilage. Condylar fibrochondrocytes and femoral hyaline chondrocytes were cultured from four, 4-week-old, New Zealand white rabbits. The production of COL2A1, COL1OA1, SOX9 and aggrecan was detected by real time-q polymerase chain reaction (RT-qPCR) and immunoblotting and the differences between them were compared statistically. Histological structures obviously differed between fibrocartilage and hyaline cartilage. COL2A1 and SOX9 were highly expressed within cell passage 2 (P2) of both fibrochondrocytes and hyaline chondrocytes, and reduced significantly after cell passage 4 (P4). The mRNA expressions of COL2A1 (p=0.05), COL10A1 (p=0.04), SOX9 (p=0.03), and aggrecan (p=0.04) were significantly higher in hyaline chondrocytes than in fibrochondrocytes, whereas the expression of COL1A1 (p=0.02) was the opposite. Immunoblotting showed similar results. We have built a simple and effective culture model of chondrocytes in vitro, and the P2 of chondrocytes is recommended for further studies. Condylar fibrocartilage and femoral hyaline cartilage have unique biological properties, and the regulatory mechanisms of endochondral ossification for the condyle should be studied independently in the future. Copyright © 2014 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  7. Membrane Core-Specific Antimicrobial Action of Cathelicidin LL-37 Peptide Switches Between Pore and Nanofibre Formation

    Science.gov (United States)

    Shahmiri, Mahdi; Enciso, Marta; Adda, Christopher G.; Smith, Brian J.; Perugini, Matthew A.; Mechler, Adam

    2016-11-01

    Membrane-disrupting antimicrobial peptides provide broad-spectrum defence against localized bacterial invasion in a range of hosts including humans. The most generally held consensus is that targeting to pathogens is based on interactions with the head groups of membrane lipids. Here we show that the action of LL-37, a human antimicrobial peptide switches the mode of action based on the structure of the alkyl chains, and not the head groups of the membrane forming lipids. We demonstrate that LL-37 exhibits two distinct interaction pathways: pore formation in bilayers of unsaturated phospholipids and membrane modulation with saturated phospholipids. Uniquely, the membrane modulation yields helical-rich fibrous peptide-lipid superstructures. Our results point at alternative design strategies for peptide antimicrobials.

  8. Dynamin regulates metaphase furrow formation and plasma membrane compartmentalization in the syncytial Drosophila embryo

    Directory of Open Access Journals (Sweden)

    Richa Rikhy

    2015-02-01

    Full Text Available The successive nuclear division cycles in the syncytial Drosophila embryo are accompanied by ingression and regression of plasma membrane furrows, which surround individual nuclei at the embryo periphery, playing a central role in embryo compartmentalization prior to cellularization. Here, we demonstrate that cell cycle changes in dynamin localization and activity at the plasma membrane (PM regulate metaphase furrow formation and PM organization in the syncytial embryo. Dynamin was localized on short PM furrows during interphase, mediating endocytosis of PM components. Dynamin redistributed off ingressed PM furrows in metaphase, correlating with stabilized PM components and the associated actin regulatory machinery on long furrows. Acute inhibition of dynamin in the temperature sensitive shibire mutant embryo resulted in morphogenetic consequences in the syncytial division cycle. These included inhibition of metaphase furrow ingression, randomization of proteins normally polarized to intercap PM and disruption of the diffusion barrier separating PM domains above nuclei. Based on these findings, we propose that cell cycle changes in dynamin orchestrate recruitment of actin regulatory machinery for PM furrow dynamics during the early mitotic cycles in the Drosophila embryo.

  9. Dynamin regulates metaphase furrow formation and plasma membrane compartmentalization in the syncytial Drosophila embryo

    Science.gov (United States)

    Rikhy, Richa; Mavrakis, Manos; Lippincott-Schwartz, Jennifer

    2015-01-01

    ABSTRACT The successive nuclear division cycles in the syncytial Drosophila embryo are accompanied by ingression and regression of plasma membrane furrows, which surround individual nuclei at the embryo periphery, playing a central role in embryo compartmentalization prior to cellularization. Here, we demonstrate that cell cycle changes in dynamin localization and activity at the plasma membrane (PM) regulate metaphase furrow formation and PM organization in the syncytial embryo. Dynamin was localized on short PM furrows during interphase, mediating endocytosis of PM components. Dynamin redistributed off ingressed PM furrows in metaphase, correlating with stabilized PM components and the associated actin regulatory machinery on long furrows. Acute inhibition of dynamin in the temperature sensitive shibire mutant embryo resulted in morphogenetic consequences in the syncytial division cycle. These included inhibition of metaphase furrow ingression, randomization of proteins normally polarized to intercap PM and disruption of the diffusion barrier separating PM domains above nuclei. Based on these findings, we propose that cell cycle changes in dynamin orchestrate recruitment of actin regulatory machinery for PM furrow dynamics during the early mitotic cycles in the Drosophila embryo. PMID:25661871

  10. Biophysical mechanism for ras-nanocluster formation and signaling in plasma membrane.

    Directory of Open Access Journals (Sweden)

    Thomas Gurry

    Full Text Available Ras GTPases are lipid-anchored G proteins, which play a fundamental role in cell signaling processes. Electron micrographs of immunogold-labeled Ras have shown that membrane-bound Ras molecules segregate into nanocluster domains. Several models have been developed in attempts to obtain quantitative descriptions of nanocluster formation, but all have relied on assumptions such as a constant, expression-level independent ratio of Ras in clusters to Ras monomers (cluster/monomer ratio. However, this assumption is inconsistent with the law of mass action. Here, we present a biophysical model of Ras clustering based on short-range attraction and long-range repulsion between Ras molecules in the membrane. To test this model, we performed Monte Carlo simulations and compared statistical clustering properties with experimental data. We find that we can recover the experimentally-observed clustering across a range of Ras expression levels, without assuming a constant cluster/monomer ratio or the existence of lipid rafts. In addition, our model makes predictions about the signaling properties of Ras nanoclusters in support of the idea that Ras nanoclusters act as an analog-digital-analog converter for high fidelity signaling.

  11. The single-giant unilamellar vesicle method reveals lysenin-induced pore formation in lipid membranes containing sphingomyelin.

    Science.gov (United States)

    Alam, Jahangir Md; Kobayashi, Toshihide; Yamazaki, Masahito

    2012-06-26

    Lysenin is a sphingomyelin (SM)-binding pore-forming toxin. To reveal the interaction of lysenin with lipid membranes, we investigated lysenin-induced membrane permeation of a fluorescent probe, calcein, through dioleoylphosphatidylcholine(DOPC)/SM, DOPC/SM/cholesterol(chol), and SM/chol membranes, using the single-giant unilamellar vesicle (GUV) method. The results clearly show that lysenin formed pores in all the membranes, through which membrane permeation of calcein occurred without disruption of GUVs. The membrane permeation began stochastically, and the membrane permeability coefficient increased over time to reach a maximum, steady value, Ps, which persisted for a long time(100--500 s), indicating that the pore concentration increases over time and finally reaches its steady value, NP s . The Ps values increased as the SM/lysenin ratio decreased, and at low concentrations of lysenin, the Ps values of SM/DOPC/chol (42/30/28)GUVs were much larger than those of SM/DOPC (58/42) GUVs. The dependence of Ps on the SM/lysenin ratio for these membranes was almost the same as that of the fraction of sodium dodecyl sulfate (SDS)-resistant lysenin oligomers, indicating that NP s increases as the SDS-resistant oligomer fraction increases. On the other hand, lysenin formed pores in GUVs of SM/chol(60/40) membrane, which is in a homogeneous liquid-ordered phase, indicating that the phase boundary is not necessary for pore formation. The Ps values of SM/chol (60/40) GUVs were smaller than those of SM/DOPC/chol (42/30/28) GUVs even though the SDS-resistant oligomer fractions were similar for both membranes, suggesting that not all of the oligomers can convert into a pore. On the basis of these results, we discuss the elementary processes of lysenin-induced pore formation.

  12. The cause and influence of sequentially assembling higher and lower deacetylated chitosans on the membrane formation of microcapsule.

    Science.gov (United States)

    Zheng, Guoshuang; Zheng, Huizhen; Xie, Hongguo; Liu, Xiudong; Yu, Weiting; Ma, Xiaojun

    2016-01-01

    Alginate-chitosan (AC) microcapsules with desired strength and biocompatibility are preferred in cell-based therapy. Sequential assembly of higher and lower deacetylated chitosans (C1 and C2 ) on alginate has produced AC1 C2 microcapsule with improved membrane strength and biocompatibility. In this article, the assembly and complexation processes of two cationic chitosans on anionic alginate were concerned, and the cause and influence of sequentially assembling chitosans on AC1 C2 microcapsules membrane formation were evaluated. It was found that C1 complexation was the key factor for deciding the membrane thickness of AC1 C2 microcapsule. Specifically, the binding amount of C2 positively related to the binding amount of C1 , which suggested the first layer by C1 complexation on alginate had no obvious resistance on the sequential cationic C2 complexation. Further analyses demonstrated that outward migration of alginate molecules and inward diffusion of both chitosans under electrostatic interaction contributed to the sequential coating of C2 on first C1 layer. Moreover, C2 complexation through the surface to inner layer of membrane helped smoothen the first layer by C1 complexation that displayed a synergy role on the formation of AC1 C2 microcapsule membrane. Therefore, the two chitosans played different roles and synergistically contributed to membrane properties that can be easily regulated with membrane complexation time.

  13. Neurokinin 1 receptor mediates membrane blebbing and sheer stress-induced microparticle formation in HEK293 cells.

    Directory of Open Access Journals (Sweden)

    Panpan Chen

    Full Text Available Cell-derived microparticles participate in intercellular communication similar to the classical messenger systems of small and macro-molecules that bind to specialized membrane receptors. Microparticles have been implicated in the regulation of a variety of complex physiopathologic processes, such as thrombosis, the control of innate and adaptive immunity, and cancer. The neurokinin 1 receptor (NK1R is a Gq-coupled receptor present on the membrane of a variety of tissues, including neurons in the central and peripheral nervous system, immune cells, endocrine and exocrine glands, and smooth muscle. The endogenous agonist of NK1R is the undecapeptide substance P (SP. We have previously described intracellular signaling mechanisms that regulate NK1R-mediated rapid cell shape changes in HEK293 cells and U373MG cells. In the present study, we show that the activation of NK1R in HEK293 cells, but not in U373MG cells, leads to formation of sheer-stress induced microparticles that stain positive with the membrane-selective fluorescent dye FM 2-10. SP-induced microparticle formation is independent of elevated intracellular calcium concentrations and activation of NK1R present on HEK293-derived microparticles triggers detectable calcium increase in SP-induced microparticles. The ROCK inhibitor Y27632 and the dynamin inhibitor dynasore inhibited membrane blebbing and microparticle formation in HEK293 cells, strongly suggesting that microparticle formation in this cell type is dependent on membrane blebbing.

  14. Influence of commercially available polyimide and formation conditions on the performance and structure of asymmetric polyimide organic solvent nanofiltration membranes

    OpenAIRE

    Lopes, Mafalda Pessoa

    2009-01-01

    Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para a obtenção do grau de Mestre em Engenharia Química e Bioquímica This work covers experimental and theoretical research related to the impact of the polymer structure of commercially available polyimide and polyetherimides as well as the formation conditions on the performance and structure of polyimide Organic Solvent Nanofiltration membranes. The influence in some membrane formation parame...

  15. The effect of high-energy extracorporeal shock waves on hyaline cartilage of adult rats in vivo.

    Science.gov (United States)

    Mayer-Wagner, Susanne; Ernst, Judith; Maier, Markus; Chiquet, Matthias; Joos, Helga; Müller, Peter E; Jansson, Volkmar; Sievers, Birte; Hausdorf, Jörg

    2010-08-01

    The aim of this study was to determine if extracorporeal shock wave therapy (ESWT) in vivo affects the structural integrity of articular cartilage. A single bout of ESWT (1500 shock waves of 0.5 mJ/mm(2)) was applied to femoral heads of 18 adult Sprague-Dawley rats. Two sham-treated animals served as controls. Cartilage of each femoral head was harvested at 1, 4, or 10 weeks after ESWT (n = 6 per treatment group) and scored on safranin-O-stained sections. Expression of tenascin-C and chitinase 3-like protein 1 (Chi3L1) was analyzed by immunohistochemistry. Quantitative real-time polymerase chain reaction (PCR) was used to examine collagen (II)alpha(1) (COL2A1) expression and chondrocyte morphology was investigated by transmission electron microscopy no changes in Mankin scores were observed after ESWT. Positive immunostaining for tenascin-C and Chi3L1 was found up to 10 weeks after ESWT in experimental but not in control cartilage. COL2A1 mRNA was increased in samples 1 and 4 weeks after ESWT. Alterations found on the ultrastructural level showed expansion of the rough-surfaced endoplasmatic reticulum, detachment of the cell membrane and necrotic chondrocytes. Extracorporeal shock waves caused alterations of hyaline cartilage on a molecular and ultrastructural level that were distinctly different from control. Similar changes were described before in the very early phase of osteoarthritis (OA). High-energy ESWT might therefore cause degenerative changes in hyaline cartilage as they are found in initial OA. Copyright 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  16. Prevalence and factors associated with scleral hyaline plaque: clinical study of older adults in southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Horowitz S

    2015-06-01

    Full Text Available Soraya Horowitz,1 Nadyr Damasceno,1 Eduardo Damasceno21Department of Ophthalmology, Hospital Naval Marcilio Dias, Rio de Janeiro, 2Department of Ophthalmology, Universidade Federal Fluminense, Niterói, BrazilPurpose: To investigate the prevalence of scleral hyaline plaque among older adults in the city of Niterói in southeastern Brazil. A second goal was to assess the correlation between scleral hyaline plaque and several age-related diseases, including eye diseases and systemic diseases.Methods: The study sample comprised 667 participants who were followed for 15 months. The study had a prospective, longitudinal, observational design that established inclusion and exclusion criteria. The following variables were selected for correlation with scleral hyaline plaque: sex, age, age range, iris color, ethnicity, presence of cataract, moderate to high myopia, age-related macular degeneration (AMD, diabetes mellitus, systemic arterial hypertension, degenerative arthritis, and osteoporosis. These correlations were assessed by means of the χ2 test and Student’s t-test. Multivariate analysis was performed to exclude factors that were potentially associated with aging exclusively but that did not have a direct relationship with hyaline plaque. Binary logistic regression was used to calculate odds ratios, significance, and confidence intervals.Results: Scleral hyaline plaques were found in 177 patients (17.54%. There was a statistically significant association between the presence of hyaline plaques and sex (female, age range (≥70 years old, ethnicity (Caucasian, cataract, moderate to high myopia, systemic arterial hypertension, degenerative arthritis, and osteoporosis (P<0.05. On multivariate binary logistic regression analysis, only female sex, age range (≥70 years, moderate to high myopia, and degenerative arthritis exhibited significant correlation.Conclusion: The prevalence of scleral hyaline plaque in the present study was higher than in

  17. The value of MDCT in diagnosis of hyaline-vascular Castleman's disease

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xiaoli [Department of Radiology, Beijing Shijitan Hospital affiliated to Capital University of Medical Sciences, Yangfangdian Tieyiyuan, Road No. 10, Haidian District, Beijing, 100038 China (China); Liu, Cheng [CT Department, Shandong Medical Imaging Research Institute (China); Wang, Rengui, E-mail: 490150302@qq.com [Department of Radiology, Beijing Shijitan Hospital affiliated to Capital University of Medical Sciences, Yangfangdian Tieyiyuan, Road No. 10, Haidian District, Beijing, 100038 China (China); Zhu, Xuejun [Dermatology Department, Beijing University First Hospital (China); Gao, Li [Department of Radiology, Beijing University First Hospital (China); Chen, Jiuhong [Healthcare, Siemens Ltd. (China)

    2012-09-15

    Purpose: Castleman's disease (CD) is an uncommon entity characterized by a massive growth of lymphoid tissue. There are two types: the hyaline-vascular (HV) type and the plasma cell (PC) type. The purpose of this study was to evaluate the clinical value of multiple detector computed tomography (MDCT) in the diagnosis and planning of treatment for hyaline-vascular CD. Materials and methods: Fifty-two cases of confirmed hyaline-vascular CD were retrospectively reviewed. Unenhanced and contrast-enhanced MDCT scans had been performed in all patients, followed by surgery and pathological analysis of the lesion. Original MDCT transverse and reconstructed images were used for image interpretation. Features of the lesion and its adjacent structures were identified. Results: The lesion was present in the thorax of 24 patients and the abdomen in 28. Obvious features of hyaline-vascular CD (especially feeding vessels and draining veins) and its adjacent structures were demonstrated on 52 patients. Conclusion: On MDCT imaging, original MDCT transverse and reconstructed images provide an excellent tool for diagnosis of hyaline-vascular CD and have high value in the determination of a treatment plan.

  18. HYALINIZING TRABECULAR ADENOMA FEIGNING PAPILLARY CARCINOMA THYROID: CASE REPORT WITH REVIEW OF LITERATURE

    Directory of Open Access Journals (Sweden)

    Kandukuri Mahesh

    2014-05-01

    Full Text Available Hyalinizing Trabecular Adenoma (HTA of the thyroid is a rare neoplasm that was first described by Carney in 1987. It is a tumor of follicular derivation with peculiar nuclear, architectural, histochemical, and immunohistochemical features. We report a case of Hyalinizing trabecular adenoma in a 36-year-old woman with enlarged thyroid lobe. Ultrasonographic features and fine needle aspiration cytology (FNAC of the enlarged thyroid was performed and the diagnosis given was Papillary carcinoma of the thyroid. The patient underwent total thyroidectomy, with a histopathological diagnosis of hyalinizing trabecular Adenoma (HTA. We present this case in view of its rarity and to discuss the clinical and diagnostic approach, including the role of FNAC, and the pathologic features of HTA with special reference to the possible differential diagnosis and also review of literature. Although rare cases of malignant Hyalinizing trabecular adenoma (HTA have been documented, this tumor should be considered a benign neoplasm or at most, a neoplasm of extremely low malignant potential, however invasion of the capsule should be considered on histopathology. An awareness of hyalinizing trabecular adenomas and their characteristic features is valuable for their recognition and management as well as for the possible prevention of over diagnosis and over treatment for benign disease

  19. Structure formation of lipid membranes: Membrane self-assembly and vesicle opening-up to octopus-like micelles

    Science.gov (United States)

    Noguchi, Hiroshi

    2013-02-01

    We briefly review our recent studies on self-assembly and vesicle rupture of lipid membranes using coarse-grained molecular simulations. For single component membranes, lipid molecules self-assemble from random gas states to vesicles via disk-shaped clusters. Clusters aggregate into larger clusters, and subsequently the large disks close into vesicles. The size of vesicles are determined by kinetics than by thermodynamics. When a vesicle composed of lipid and detergent types of molecules is ruptured, a disk-shaped micelle called bicelle can be formed. When both surfactants have negligibly low critical micelle concentration, it is found that bicelles connected with worm-like micelles are also formed depending on the surfactant ratio and spontaneous curvature of the membrane monolayer.

  20. Chitosan facilitates structure formation of the salivary gland by regulating the basement membrane components.

    Science.gov (United States)

    Yang, Tsung-Lin; Hsiao, Ya-Chuan

    2015-10-01

    Tissue structure is important for inherent physiological function and should be recapitulated during tissue engineering for regenerative purposes. The salivary gland is a branched organ that is responsible for saliva secretion and regulation. The salivary glands develop from epithelial-mesenchymal interactions, and depend on the support of the basement membrane (BM). Chitosan-based biomaterials have been demonstrated to be competent in facilitating the formation of salivary gland tissue structure. However, the underlying mechanisms have remained elusive. In the developing submandibular gland (SMG), the chitosan effect was found to diminish when collagen and laminin were removed from cultured SMG explants. Chitosan increased the expression of BM components including collagen, laminin, and heparan sulfate proteoglycan, and also facilitated BM components and the corresponding receptors to be expressed in tissue-specific patterns beneficial for SMG branching. The chitosan effect decreased when either laminin components or receptors were inhibited, as well when the downstream signaling was blocked. Our results revealed that chitosan promotes salivary glands branching through the BM. By regulating BM components and receptors, chitosan efficiently stimulated downstream signaling to facilitate salivary gland branching. The present study revealed the underlying mechanism of the chitosan effect in engineering SMG structure formation.

  1. Magnetic resonance imaging of hyaline cartilage regeneration in neocartilage graft implantation.

    Science.gov (United States)

    Tan, C F; Ng, K K; Ng, S H; Cheung, Y C

    2003-12-01

    The purpose of this study was to investigate the regenerative potential of hyaline cartilage in a neocartilage graft implant with the aid of MR cartilage imaging using a rabbit model. Surgical osteochondral defects were created in the femoral condyles of 30 mature New Zealand rabbits. The findings of neocartilage in autologous cartilage grafts packed into osteochondral defects were compared with control group of no implant to the osteochondral defect. The outcome of the implantations was correlated with histologic and MR cartilage imaging findings over a 3-month interval. Neocartilage grafts packed into osteochondral defects showed regeneration of hyaline cartilage at the outer layer of the implant using MR cartilage imaging. Fibrosis of fibrocartilage developed at the outer layer of the autologous cartilage graft together with an inflammatory reaction within the osteochondral defect. This animal study provides evidence of the regenerative ability of hyaline cartilage in neocartilage transplants to repair articular cartilage.

  2. Effect of different phospholipid-cholesterol membrane compositions on liposome-mediated formation of calcium phosphates.

    Science.gov (United States)

    Skrtic, D; Eanes, E D

    1992-03-01

    The present report compares the effects of different membrane phospholipid (PL)-cholesterol compositions on the kinetics of liposome-mediated formation of calcium phosphates from metastable solutions (2.25 mM CaCl2; 1.5 mM KH2PO4) at 22 degrees C, pH 7.4 and 240 mOsm. In most experiments, the liposomes were composed of 7:2:X mixtures of phosphatidylcholine (PC), neutral or acidic phospholipids, and cholesterol (Chol, X = 0, 10, 35, or 50 mol%). The neutral phospholipids (NPL) examined, in addition to PC, were phosphatidylethanolamine (PE) and sphingomyelin (Sph), and the acidic phospholipids (APL) examined were dicetylphosphate (DCP), dioleolylphosphatidylglycerol (DOPG), dioleolylphosphatidic acid (DOPA), phosphatidylserine (PS) and phosphatidylinositol (PI). The 7:2:X liposomes did not initiate mineralization in metasable external solutions per se or, with the exception of DOPA, show extensive Ca-PL binding. However, solution Ca2+ losses due to precipitation occurred when the liposomes were encapsulated with 50 mM KH2PO4 and made permeable to external Ca2+ with X-537A. The extent of these Ca2+ losses was sensitive to both the phospholipid and Chol makeup of the membrane. Moderate-to-extensive intraliposomal precipitation occurred in all 7PC:2APL and 7PC:2NPL liposomes containing 0 or 10 mol% Chol. In contrast, at 50 mol% Chol, mineralization inside all liposomes was negligible. The only significant discriminating effect on internal mineralization among the different phospholipids was observed at 35 mol% Chol, where mineral accumulations ranged from negligible to moderate. At 0 or 10 mol% Chol, extraliposomal precipitation was extensive in all but DOPA- and PS-containing liposomes.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. Effect of integral proteins in the phase stability of a lipid bilayer: Application to raft formation in cell membranes

    Science.gov (United States)

    Gómez, Jordi; Sagués, Francesc; Reigada, Ramon

    2010-04-01

    The existence of lipid rafts is a controversial issue. The affinity of cholesterol for saturated lipids is manifested in macroscopic phase separation in model membranes, and is believed to be the thermodynamic driving force for raft formation. However, there is no clear reason to explain the small (nanometric) size of raft domains in cell membranes. In a recent paper Yethiraj and Weisshaar [Biophys. J. 93, 3113 (2007)] proposed that the effect of neutral integral membrane proteins may prevent from the formation of large lipid domains. In this paper we extend this approach by studying the effect of the protein size, as well as the lipid-protein interaction. Depending on these factors, two different mechanisms for nanodomain stabilization are shown to be possible for static proteins. The application of these results to a biological context is discussed.

  4. Hyaline cartilage cells outperform mandibular condylar cartilage cells in a TMJ fibrocartilage tissue engineering application.

    Science.gov (United States)

    Wang, L; Lazebnik, M; Detamore, M S

    2009-03-01

    To compare temporomandibular joint (TMJ) condylar cartilage cells in vitro to hyaline cartilage cells cultured in a three-dimensional (3D) environment for tissue engineering of mandibular condylar cartilage. Mandibular condylar cartilage and hyaline cartilage cells were harvested from pigs and cultured for 6 weeks in polyglycolic acid (PGA) scaffolds. Both types of cells were treated with glucosamine sulfate (0.4 mM), insulin-like growth factor-I (IGF-I) (100 ng/ml) and their combination. At weeks 0 and 6, cell number, glycosaminoglycan (GAG) and collagen content were determined, types I and II collagen were visualized by immunohistochemistry and GAGs were visualized by histology. Hyaline cartilage cells produced from half an order to a full order of magnitude more GAGs and collagen than mandibular condylar cartilage cells in 3D culture. IGF-I was a highly effective signal for biosynthesis with hyaline cartilage cells, while glucosamine sulfate decreased cell proliferation and biosynthesis with both types of cells. In vitro culture of TMJ condylar cartilage cells produced a fibrous tissue with predominantly type I collagen, while hyaline cartilage cells formed a fibrocartilage-like tissue with types I and II collagen. The combination of IGF and glucosamine had a synergistic effect on maintaining the phenotype of TMJ condylar cells to generate both types I and II collagen. Given the superior biosynthetic activity by hyaline cartilage cells and the practical surgical limitations of harvesting cells from the TMJ of a patient requiring TMJ reconstruction, cartilage cells from elsewhere in the body may be a potentially better alternative to cells harvested from the TMJ for TMJ tissue engineering. This finding may also apply to other fibrocartilages such as the intervertebral disc and knee meniscus in applications where a mature cartilage cell source is desired.

  5. Formation of domain structure of erythrocyte membrane in Wistar rat fed with CeCl3 per os

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    To explore the possibility of absorption of lanthanides via digestive duct and their effects on the membrane structure and permeability of erythrocytes,the fine structure of erythrocyte membrane from Wistar rats,fed for 70 days of daily administration per os with 20 mg CeCl3/kg weight,was imaged by means of atomic force microscopy and FT-IR deconvolution spectra.The results show that,although the erythrocytes maintain the intact shape,the change of secondary structure,aggregation and crosslinking of the protein particles of membrane surface and the enlarged lipid regions lead to the domain structure formation.This structure might be responsible for the increasing permeability of erythrocyte membrane.

  6. Oral pulse or hyaline ring granuloma: A case report and a brief review

    Directory of Open Access Journals (Sweden)

    Swetha Acharya

    2015-01-01

    Full Text Available Pulse or hyaline ring granulomas are rare but are well-defined oral and extraoral lesions due to implantation of the cellulose moiety of plant foods in contrast starch components. A unique form as reactive gingival growth showing histologic features of oral pulse or hyaline ring granuloma (OPHRG which had resulted from implantation of food particles of plant or vegetable origin into the periodontium has been illustrated. Such a presentation is attributable to compromised periodontal health and poor oral hygiene favoring the implantation of food particles has been described here along with a literature update on OPHRG.

  7. Hyalinizing trabecular tumor of the thyroid gland: characteristic features on ultrasonography.

    Science.gov (United States)

    Kobayashi, Kaoru; Hirokawa, Mitsuyoshi; Jikuzono, Tomoo; Fukata, Shuji; Amino, Nobuyuki; Miyauchi, Akira; Nakamura, Yasushi

    2007-03-01

    We report a case of hyalinizing trabecular tumor of the thyroid gland and describe the characteristic ultrasonographic features of this tumor. This was a rare tumor of follicular cell origin with a trabecular pattern of growth and marked intratrabecular hyalinization. The tumor had an irregular shape, a delicately jagged border, and hypoechoic and heterogeneous internal echoes on B-mode ultrasonography. Very rich intratumoral blood flow, the so-called "tumor inferno" was evident on power Doppler ultrasonography. In the clinical management of thyroid nodules, clinicians should be aware of this peculiar type of thyroid tumor and its characteristic ultrasonographic findings.

  8. Quantitative assessment of hyaline cartilage elasticity during optical clearing using optical coherence elastography

    Science.gov (United States)

    Liu, Chih-Hao; Singh, Manmohan; Li, Jiasong; Han, Zhaolong; Wu, Chen; Wang, Shang; Idugboe, Rita; Raghunathan, Raksha; Zakharov, Valery P.; Sobol, Emil N.; Tuchin, Valery V.; Twa, Michael; Larin, Kirill V.

    2015-03-01

    We report the first study on using optical coherence elastography (OCE) to quantitatively monitor the elasticity change of the hyaline cartilage during the optical clearing administrated by glucose solution. The measurement of the elasticity is verified using uniaxial compression test, demonstrating the feasibility of using OCE to quantify the Young's modulus of the cartilage tissue. As the results, we found that the stiffness of the hyaline cartilage increases during the optical clearing of the tissue. This study might be potentially useful for the early detection of osteoarthritis disease.

  9. Juvenile hyaline fibromatosis and infantile systemic hyalinosis: Divergent expressions of the same genetic defect?

    Directory of Open Access Journals (Sweden)

    Dhingra Mandeep

    2008-01-01

    Full Text Available We describe here a three year-old girl with classic clinical and histological features of juvenile hyaline fibromatosis. We found a history of similar skin findings in her eldest sister, in whom the disorder took a rapidly progressive and fatal course in the second year of life, suggesting either a very severe form of juvenile hyaline fibromatosis, or the possibility of infantile systemic hyalinosis. The similarities and differences between these two described types of hyalinoses have been reviewed in reference to the present report.

  10. Electrolytic membrane formation of fluoroalkyl polymer using a UV-radiation-based grafting technique and sulfonation

    Energy Technology Data Exchange (ETDEWEB)

    Shironita, Sayoko; Mizoguchi, Satoko; Umeda, Minoru, E-mail: mumeda@vos.nagaokaut.ac.jp [Department of Materials Science and Technology, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka 940-2188, Niigata (Japan)

    2011-03-15

    A sulfonated fluoroalkyl graft polymer (FGP) membrane was prepared as a polymer electrolyte. First, the FGP membrane was grafted with styrene under UV irradiation. The grafted FGP was then sulfonated to functionalize it for proton conductivity. The grafting degree of the membrane increased with increasing grafting time during UV irradiation. The proton conductivity of the membrane increased with increasing grafting degree. The swelling ratio was independent of the grafting time, however, the water uptake increased with increasing grafting degree. Based on these results, it was found that the UV-initiated styrene grafting occurred along the membrane thickness direction. Moreover, the membrane was embedded within the glass fibers of the composite. This composite electrolytic membrane had 1.15 times the proton conductivity of a Nafion 117 membrane.

  11. Similar hyaline-like cartilage repair of osteochondral defects in rabbits using isotropic and anisotropic collagen scaffolds

    NARCIS (Netherlands)

    Mulder, E.L.W. de; Hannink, G.J.; Kuppevelt, T.H. van; Daamen, W.F.; Buma, P.

    2014-01-01

    Lesions in knee joint articular cartilage (AC) have limited repair capacity. Many clinically available treatments induce a fibrous-like cartilage repair instead of hyaline cartilage. To induce hyaline cartilage repair, we hypothesized that type I collagen scaffolds with fibers aligned perpendicular

  12. Bax Activation Initiates the Assembly of a Multimeric Catalyst that Facilitates Bax Pore Formation in Mitochondrial Outer Membranes

    Science.gov (United States)

    Kushnareva, Yulia; Andreyev, Alexander Y.; Kuwana, Tomomi; Newmeyer, Donald D.

    2012-01-01

    Bax/Bak-mediated mitochondrial outer membrane permeabilization (MOMP) is essential for “intrinsic” apoptotic cell death. Published studies used synthetic liposomes to reveal an intrinsic pore-forming activity of Bax, but it is unclear how other mitochondrial outer membrane (MOM) proteins might facilitate this function. We carefully analyzed the kinetics of Bax-mediated pore formation in isolated MOMs, with some unexpected results. Native MOMs were more sensitive than liposomes to added Bax, and MOMs displayed a lag phase not observed with liposomes. Heat-labile MOM proteins were required for this enhanced response. A two-tiered mathematical model closely fit the kinetic data: first, Bax activation promotes the assembly of a multimeric complex, which then catalyzes the second reaction, Bax-dependent pore formation. Bax insertion occurred immediately upon Bax addition, prior to the end of the lag phase. Permeabilization kinetics were affected in a reciprocal manner by [cBid] and [Bax], confirming the “hit-and-run” hypothesis of cBid-induced direct Bax activation. Surprisingly, MOMP rate constants were linearly related to [Bax], implying that Bax acts non-cooperatively. Thus, the oligomeric catalyst is distinct from Bax. Moreover, contrary to common assumption, pore formation kinetics depend on Bax monomers, not oligomers. Catalyst formation exhibited a sharp transition in activation energy at ∼28°C, suggesting a role for membrane lipid packing. Furthermore, catalyst formation was strongly inhibited by chemical antagonists of the yeast mitochondrial fission protein, Dnm1. However, the mammalian ortholog, Drp1, was undetectable in mitochondrial outer membranes. Moreover, ATP and GTP were dispensable for MOMP. Thus, the data argue that oligomerization of a catalyst protein, distinct from Bax and Drp1, facilitates MOMP, possibly through a membrane-remodeling event. PMID:23049480

  13. Magnetic resonance tomography (MRT) of the knee joint: Meniscus, cruciate ligaments and hyaline cartilage. Magnetresonanztomographie (MRT) des Kniegelenks: Meniskus, Kreuzbaender und hyaliner Gelenkknorpel

    Energy Technology Data Exchange (ETDEWEB)

    Hodler, J. (Radiologie, Universitaetsspital, Zurich (Switzerland) Orthopaedische Universitaetsklinik Balgrist, Zurich (Switzerland). Radiologische Abt.); Buess, E. (Orthopaedische Universitaetsklinik Balgrist, Zurich (Switzerland)); Rodriguez, M. (Orthopaedische Universitaetsklinik Balgrist, Zurich (Switzerland)); Imhoff, A. (Orthopaedische Universitaetsklinik Balgrist, Zurich (Switzerland))

    1993-08-01

    The use of MRT for diagnosing injury to the meniscus, the cruciate ligaments and hyaline cartilage was evaluated retrospectively in 82 knee joints without any knowledge of operative findings. In 49 cases the results were verified by arthroscopy and in 33 cases by arthrotomy. Sensitivity, specificity and diagnostic accuracy of MRT for meniscus lesions was 73.9%, 96.9%, and 94.6%. Corresponding values for lesions of the anterior cruciate ligament were 88.9%, 96.6%, and 94.7%, and for lesions of the hyaline cartilage 62.6%, 96.1%, and 87.9%, respectively. In addition to its high specificity, MRT proved accurate in excluding lesions of the meniscus (97.1%) of the anterior cruciate ligament (96.6%) and of hyaline cartilage (88.8%). A negative finding on MRT therefore makes the presence of a lesion of the meniscus, cruciate ligaments of cartilage unlikely. In such cases one is justified in delaying the use of arthroscopy or arthrotomy. (orig.)

  14. In-situ biofilm characterization in membrane systems using Optical Coherence Tomography: formation, structure, detachment and impact of flux change.

    Science.gov (United States)

    Dreszer, C; Wexler, A D; Drusová, S; Overdijk, T; Zwijnenburg, A; Flemming, H-C; Kruithof, J C; Vrouwenvelder, J S

    2014-12-15

    Biofouling causes performance loss in spiral wound nanofiltration (NF) and reverse osmosis (RO) membrane operation for process and drinking water production. The development of biofilm formation, structure and detachment was studied in-situ, non-destructively with Optical Coherence Tomography (OCT) in direct relation with the hydraulic biofilm resistance and membrane performance parameters: transmembrane pressure drop (TMP) and feed-channel pressure drop (FCP). The objective was to evaluate the suitability of OCT for biofouling studies, applying a membrane biofouling test cell operated at constant crossflow velocity (0.1 m s(-1)) and permeate flux (20 L m(-2)h(-1)). In time, the biofilm thickness on the membrane increased continuously causing a decline in membrane performance. Local biofilm detachment was observed at the biofilm-membrane interface. A mature biofilm was subjected to permeate flux variation (20 to 60 to 20 L m(-2)h(-1)). An increase in permeate flux caused a decrease in biofilm thickness and an increase in biofilm resistance, indicating biofilm compaction. Restoring the original permeate flux did not completely restore the original biofilm parameters: After elevated flux operation the biofilm thickness was reduced to 75% and the hydraulic resistance increased to 116% of the original values. Therefore, after a temporarily permeate flux increase the impact of the biofilm on membrane performance was stronger. OCT imaging of the biofilm with increased permeate flux revealed that the biofilm became compacted, lost internal voids, and became more dense. Therefore, membrane performance losses were not only related to biofilm thickness but also to the internal biofilm structure, e.g. caused by changes in pressure. Optical Coherence Tomography proved to be a suitable tool for quantitative in-situ biofilm thickness and morphology studies which can be carried out non-destructively and in real-time in transparent membrane biofouling monitors.

  15. In-situ biofilm characterization in membrane systems using Optical Coherence Tomography: Formation, structure, detachment and impact of flux change

    KAUST Repository

    Dreszer, C.

    2014-12-01

    Biofouling causes performance loss in spiral wound nanofiltration (NF) and reverse osmosis (RO) membrane operation for process and drinking water production. The development of biofilm formation, structure and detachment was studied in-situ, non-destructively with Optical Coherence Tomography (OCT) in direct relation with the hydraulic biofilm resistance and membrane performance parameters: transmembrane pressure drop (TMP) and feed-channel pressure drop (FCP). The objective was to evaluate the suitability of OCT for biofouling studies, applying a membrane biofouling test cell operated at constant crossflow velocity (0.1 m s-1) and permeate flux (20 L m-2h-1).In time, the biofilm thickness on the membrane increased continuously causing a decline in membrane performance. Local biofilm detachment was observed at the biofilm-membrane interface. A mature biofilm was subjected to permeate flux variation (20 to 60 to 20 L m-2h-1). An increase in permeate flux caused a decrease in biofilm thickness and an increase in biofilm resistance, indicating biofilm compaction. Restoring the original permeate flux did not completely restore the original biofilm parameters: After elevated flux operation the biofilm thickness was reduced to 75% and the hydraulic resistance increased to 116% of the original values. Therefore, after a temporarily permeate flux increase the impact of the biofilm on membrane performance was stronger. OCT imaging of the biofilm with increased permeate flux revealed that the biofilm became compacted, lost internal voids, and became more dense. Therefore, membrane performance losses were not only related to biofilm thickness but also to the internal biofilm structure, e.g. caused by changes in pressure.Optical Coherence Tomography proved to be a suitable tool for quantitative in-situ biofilm thickness and morphology studies which can be carried out non-destructively and in real-time in transparent membrane biofouling monitors.

  16. Epithelial membrane protein-2 promotes endometrial tumor formation through activation of FAK and Src.

    Directory of Open Access Journals (Sweden)

    Maoyong Fu

    Full Text Available Endometrial cancer is the most common gynecologic malignancy diagnosed among women in developed countries. One recent biomarker strongly associated with disease progression and survival is epithelial membrane protein-2 (EMP2, a tetraspan protein known to associate with and modify surface expression of certain integrin isoforms. In this study, we show using a xenograft model system that EMP2 expression is necessary for efficient endometrial tumor formation, and we have started to characterize the mechanism by which EMP2 contributes to this malignant phenotype. In endometrial cancer cells, the focal adhesion kinase (FAK/Src pathway appears to regulate migration as measured through wound healing assays. Manipulation of EMP2 levels in endometrial cancer cells regulates the phosphorylation of FAK and Src, and promotes their distribution into lipid raft domains. Notably, cells with low levels of EMP2 fail to migrate and poorly form tumors in vivo. These findings reveal the pivotal role of EMP2 in endometrial cancer carcinogenesis, and suggest that the association of elevated EMP2 levels with endometrial cancer prognosis may be causally linked to its effect on integrin-mediated signaling.

  17. Sewage sludge treatment in a thermophilic membrane reactor (TMR): factors affecting foam formation.

    Science.gov (United States)

    Collivignarelli, Maria Cristina; Castagnola, Federico; Sordi, Marco; Bertanza, Giorgio

    2017-01-01

    Foam formation in the excess sludge treatment facilities of biological wastewater treatment plants (WWTPs) may represent a critical issue as it could lead to several operative problems and reduce the overall plant performance. This trouble also affects a novel technology recently proposed for sludge minimization, the thermophilic membrane reactor (TMR), operating with alternate aeration/non-aeration cycles. This technology, which has proven to be extremely resilient and suitable for treating industrial wastewater of different nature, demonstrated a high potential also as a solution for integrating existing WWTPs, aiming at the "zero sludge production." In this work, an experimental study was conducted with a TMR pilot plant (fed daily with thickened sewage sludge) by adjusting the duration of aeration/non-aeration alternate cycles. Extracellular polymeric substance (EPS) concentration (and its soluble and bound fractions) has been monitored along with foaming power indices. The results highlight that foaming can be correlated to the presence of soluble protein fraction of EPS. Moreover, EPS production seems to be reduced by increasing the duration of the non-aeration cycles: optimal operating conditions resulted 2 h of aeration followed by 6 h of non-aeration. These conditions allow to obtain an EPS concentration of 500 mg L(-1) with respect to 2300 mg L(-1) measured at the beginning of experimental work.

  18. Toosendanin interferes with pore formation of botulinum toxin type A in PC12 cell membrane

    Institute of Scientific and Technical Information of China (English)

    Mu-feng LI; Yu-liang SHI

    2006-01-01

    Aim: Botulinum neurotoxins (BoNT) abort the process of neurotransmitter release at presynaptic motor nerve terminals, causing muscle paralysis. The ability of botulinum toxin to produce its effect is dependent on the ability of the light chain to cleave the SNARE proteins associated with transmitter release. Translocation of the light chain protease through the heavy chain-formed channel is a pivotal step in the intoxication process. Toosendanin (TSN), a triterpenoid derivative extracted from a Chinese traditional medicine, has been demonstrated to be an effective cure for experimental botulism. This study was designed to explore the antibotulismic mechanisms of toosendanin. Methods: The inside-out singlechannel recording patch-clamp technique was used to record the BoNT/A-induced currents in the presence and absence of TSN. Results: Channel formation was delayed and the sizes of the channels were reduced in the TSN-treated PC12cell membrane. Conclusion: The antibotulismic effect of TSN might occur via interference with toxin translocation.

  19. Analysis of outer membrane vesicle protein involved in biofilm formation of Helicobacter pylori.

    Science.gov (United States)

    Yonezawa, Hideo; Osaki, Takako; Woo, Timothy; Kurata, Satoshi; Zaman, Cynthia; Hojo, Fuhito; Hanawa, Tomoko; Kato, Shuichi; Kamiya, Shigeru

    2011-12-01

    Helicobacter pylori is one of the most common causes of bacterial infection in humans. Infection with H. pylori is closely associated with gastritis and peptic ulcers and is a risk factor for gastric cancer and mucosa-associated lymphoid tissue lymphoma. H. pylori forms biofilms on glass surfaces at the air-liquid interface in in-vitro batch cultures. We previously reported that strain TK1402 showed a strong biofilm-forming ability in vitro. We also suggested the outer membrane vesicles (OMV) produced by strain TK1402 might be related to its biofilm forming ability. In the present study, we analyzed the protein profile of the OMV produced by strain TK1402 and found a unique 22-kDa protein in TK1402 OMV cultured for 2-3 days. In addition, this protein could not be detected in the OMVs produced by other H. pylori strains. These results suggest that the 22-kDa protein is involved in effective biofilm formation by strain TK1402. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. Fast formation of NaA zeolite membrane in the microwave field

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    NaA zeolite membrane was successfully synthesized on the porous α-Al2O3 support by microwave heating. The synthesis of NaA zeolite membrane in the microwave field only needs 15 min and the synthesis time is 10 times shorter than that by conventional heating. SEM characterization indicates that the zeolite crystals in the NaA zeolite membrane synthesized by microwave heating are uniform in size; the membrane thickness is about 4 μm and is thinner than that of the NaA zeolite membrane synthesized by conventional heating. Gas permeation studies indicate that the permeances of the NaA zeolite membrane synthesized by microwave heating are 3-4 times higher than those of the NaA zeolite membrane synthesized by conventional heating, while their permselectivities are comparable.

  1. Computed tomography findings in patients with pulmonary hyalinizing granulomas: a case report; Granulomas hialinizantes pulmonares: aspectos na tomografia computadorizada - relato de caso

    Energy Technology Data Exchange (ETDEWEB)

    Marchiori, Edson [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Dept. de Radiologia]. E-mail: edmarchiori@zipmail.com.br; Valiante, Paulo Marcos [Universidade Federal, Rio de Janeiro, RJ (Brazil). Faculdade de Medicina. Dept. de Patologia; Correia, Ana Helena Pereira; Carneiro, Leonardo Hoehl; Caldas, Carolina Rodrigues [Hospital Universitario Clementino Fraga Filho, Rio de Janeiro, RJ (Brazil). Servico de Anatomia Patologica; Souza Junior, Arthur Soares [Faculdade de Medicina de Sao Jose do Rio Preto (FAMERP), SP (Brazil). Dept. de Radiologia

    2003-12-01

    Hyalinizing granulomas are benign fibrotic lesions that generally present multiple nodules seen on radiological examinations, which are frequently cavitary and/or calcified lesions. We report a case of a 28 year-old-woman with hyalinizing granulomas probably secondary to a previous tuberculosis infection. Hyalinizing granulomas should be included in the differential diagnosis of patients with multiple pulmonary nodules. (author)

  2. Irreversible fouling of membrane bioreactors due to formation of a non-biofilm gel-like layer

    DEFF Research Database (Denmark)

    Poorasgari, Eskandar; Larsen, Poul; Zheng, Xing

    2013-01-01

    Extra-cellular polymeric substances (EPS), known to contribute to fouling in membrane bio-reactors (MBR)s, are generally divided into bound and free EPS. The free EPS are able to form a gel-like layer on the membrane active surface. The mechanisms involved in formation of such layer and its effects...... with the amount of the humic-like substances retained during filtration as predicted by gel growth theory. A low pressure backwash could re-establish the water flux only up to 70%....

  3. Ultrathin carbon nanotube-DNA hybrid membrane formation by simple physical adsorption onto a thin alumina substrate

    Energy Technology Data Exchange (ETDEWEB)

    Guo Min; Lv Wei; Zhang Shaobo; Jin Fengmin; Wang Qi; Ling Guowei; Yang Quanhong, E-mail: qhyangcn@tju.edu.cn [Key Laboratory for Green Chemical Technology of the Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China)

    2010-07-16

    Ultrathin carbon nanotube membranes can be prepared on alumina substrates by a facile immersion-adsorption approach, which involves two steps, the first step DNA wrapping and the second step uniform adsorption of the DNA-wrapped nanotubes onto porous alumina. In this approach, DNA wrapping imparts a hydrophilic nature to the carbon nanotubes, which enhances the interaction between the nanotubes and hydrophilic porous alumina and results in the self-assembly formation of ultrathin nanotube membranes with well-controlled thickness, biocompatibility, conductivity and optical properties.

  4. INFLUENCE OF ALCOHOL-BASED NONSOLVENTS ON THE FORMATION AND MORPHOLOGY OF PVDF MEMBRANES IN PHASE INVERSION PROCESS

    Institute of Scientific and Technical Information of China (English)

    Dan-ying Zuo; Bao-ku Zhu; Jian-hua Cao; You-yi Xu

    2006-01-01

    Through the preparation of PVDF membranes using various nonsolvent coagulation baths following the phase inversion process, the influence of alcohol-based nonsolvents on the formation and structure of PVDF membranes were investigated. The light scattering and light transmission measurements were used to characterize the equilibrium phase diagram and the gelation speed, respectively. The locations of the crystallization-induced gelation boundaries for various systems and precipitation processes were explained from the corresponding thermodynamic and kinetic parameters. It was found that the better affinity between alcohol-based nonsolvents and DMAc solvent caused the gelation boundaries further away from the PVDF-DMAc axis with the coagulation bath varying from water, methanol, ethanol to iso-propanol. Due to the lower exchange rate of DMAc and alcohols, the delayed demixing took place for the membrane-forming using alcohols as baths, and the delayed time became longer when the coagulation bath was changed from methanol, ethanol to iso-propanol.The characterization results of membranes indicate that the influence of nonsolvents on the phase diagram and the precipitation process are in agreement with those on the membrane morphology. The better thermodynamic stability and a low exchange diffusion rate of PVDF/DMAc/alcohols favor the liquid-solid phase separation in gelation process, and therefore yield the membranes with a porous upper surface, a particular bottom surface and symmetrical structure.

  5. Quantification of collagen distributions in rat hyaline and fibro cartilages based on second harmonic generation imaging

    Science.gov (United States)

    Zhu, Xiaoqin; Liao, Chenxi; Wang, Zhenyu; Zhuo, Shuangmu; Liu, Wenge; Chen, Jianxin

    2016-10-01

    Hyaline cartilage is a semitransparent tissue composed of proteoglycan and thicker type II collagen fibers, while fibro cartilage large bundles of type I collagen besides other territorial matrix and chondrocytes. It is reported that the meniscus (fibro cartilage) has a greater capacity to regenerate and close a wound compared to articular cartilage (hyaline cartilage). And fibro cartilage often replaces the type II collagen-rich hyaline following trauma, leading to scar tissue that is composed of rigid type I collagen. The visualization and quantification of the collagen fibrillar meshwork is important for understanding the role of fibril reorganization during the healing process and how different types of cartilage contribute to wound closure. In this study, second harmonic generation (SHG) microscope was applied to image the articular and meniscus cartilage, and textural analysis were developed to quantify the collagen distribution. High-resolution images were achieved based on the SHG signal from collagen within fresh specimens, and detailed observations of tissue morphology and microstructural distribution were obtained without shrinkage or distortion. Textural analysis of SHG images was performed to confirm that collagen in fibrocartilage showed significantly coarser compared to collagen in hyaline cartilage (p imaging degenerative tissues or assessing wound repair following cartilage injury.

  6. Juvenile hyaline fibromatosis and infantile systemic hyalinosis: a unifying term and a proposed grading system.

    Science.gov (United States)

    Nofal, Ahmad; Sanad, Mohammad; Assaf, Magda; Nofal, Eman; Nassar, Amani; Almokadem, Sahar; Attwa, Enayat; Elmosalamy, Khaled

    2009-10-01

    It has been suggested that juvenile hyaline fibromatosis and infantile systemic hyalinosis represent different severities of the same disease. We sought to redefine these disorders clearly to establish a common inclusive terminology. The study included two children with early onset of similar pink papulonodular skin lesions and marked gingival hyperplasia. The first case was characterized by flexion contractures of the large joints, fractures, persistent diarrhea, recurrent chest infections, and retarded physical growth. The second patient had large swellings on the scalp and knees without systemic involvement. Radiologic examination revealed fractures and osteolytic bone lesions in the first case, and soft tissue masses in the second case. Laboratory tests showed anemia in both cases, and hypogammaglobulinemia, hypoalbuminemia, and electrolyte imbalance in the first case. Histopathological and ultrastructural evaluation demonstrated hyalinized fibrous tissue in the dermis in both cases. Genetic studies were unavailable. Juvenile hyaline fibromatosis and infantile systemic hyalinosis share many common features that strongly support consideration of these conditions as different expressions of the same disorder. We propose a common term, "hyaline fibromatosis syndrome," which can be divided into mild, moderate, and severe subtypes.

  7. Generation of hyaline cartilaginous tissue from mouse adult dermal fibroblast culture by defined factors

    Science.gov (United States)

    Hiramatsu, Kunihiko; Sasagawa, Satoru; Outani, Hidetatsu; Nakagawa, Kanako; Yoshikawa, Hideki; Tsumaki, Noriyuki

    2011-01-01

    Repair of cartilage injury with hyaline cartilage continues to be a challenging clinical problem. Because of the limited number of chondrocytes in vivo, coupled with in vitro de-differentiation of chondrocytes into fibrochondrocytes, which secrete type I collagen and have an altered matrix architecture and mechanical function, there is a need for a novel cell source that produces hyaline cartilage. The generation of induced pluripotent stem (iPS) cells has provided a tool for reprogramming dermal fibroblasts to an undifferentiated state by ectopic expression of reprogramming factors. Here, we show that retroviral expression of two reprogramming factors (c-Myc and Klf4) and one chondrogenic factor (SOX9) induces polygonal chondrogenic cells directly from adult dermal fibroblast cultures. Induced cells expressed marker genes for chondrocytes but not fibroblasts, i.e., the promoters of type I collagen genes were extensively methylated. Although some induced cell lines formed tumors when subcutaneously injected into nude mice, other induced cell lines generated stable homogenous hyaline cartilage–like tissue. Further, the doxycycline-inducible induction system demonstrated that induced cells are able to respond to chondrogenic medium by expressing endogenous Sox9 and maintain chondrogenic potential after substantial reduction of transgene expression. Thus, this approach could lead to the preparation of hyaline cartilage directly from skin, without generating iPS cells. PMID:21293062

  8. Uninduced adipose-derived stem cells repair the defect of full-thickness hyaline cartilage.

    Science.gov (United States)

    Zhang, Hai-Ning; Li, Lei; Leng, Ping; Wang, Ying-Zhen; Lv, Cheng-Yu

    2009-04-01

    To testify the effect of the stem cells derived from the widely distributed fat tissue on repairing full-thickness hyaline cartilage defects. Adipose-derived stem cells (ADSCs) were derived from adipose tissue and cultured in vitro. Twenty-seven New Zealand white rabbits were divided into three groups randomly. The cultured ADSCs mixed with calcium alginate gel were used to fill the full-thickness hyaline cartilage defects created at the patellafemoral joint, and the defects repaired with gel or without treatment served as control groups. After 4, 8 and 12 weeks, the reconstructed tissue was evaluated macroscopically and microscopically. Histological analysis and qualitative scoring were also performed to detect the outcome. Full thickness hyaline cartilage defects were repaired completely with ADSCs-derived tissue. The result was better in ADSCs group than the control ones. The microstructure of reconstructed tissue with ADSCs was similar to that of hyaline cartilage and contained more cells and regular matrix fibers, being better than other groups. Plenty of collagen fibers around cells could be seen under transmission electron microscopy. Statistical analysis revealed a significant difference in comparison with other groups at each time point (t equal to 4.360, P less than 0.01). These results indicate that stem cells derived from mature adipose without induction possess the ability to repair cartilage defects.

  9. Stepwise visualization of membrane pore formation by suilysin, a bacterial cholesterol-dependent cytolysin.

    Science.gov (United States)

    Leung, Carl; Dudkina, Natalya V; Lukoyanova, Natalya; Hodel, Adrian W; Farabella, Irene; Pandurangan, Arun P; Jahan, Nasrin; Pires Damaso, Mafalda; Osmanović, Dino; Reboul, Cyril F; Dunstone, Michelle A; Andrew, Peter W; Lonnen, Rana; Topf, Maya; Saibil, Helen R; Hoogenboom, Bart W

    2014-12-02

    Membrane attack complex/perforin/cholesterol-dependent cytolysin (MACPF/CDC) proteins constitute a major superfamily of pore-forming proteins that act as bacterial virulence factors and effectors in immune defence. Upon binding to the membrane, they convert from the soluble monomeric form to oligomeric, membrane-inserted pores. Using real-time atomic force microscopy (AFM), electron microscopy (EM), and atomic structure fitting, we have mapped the structure and assembly pathways of a bacterial CDC in unprecedented detail and accuracy, focussing on suilysin from Streptococcus suis. We show that suilysin assembly is a noncooperative process that is terminated before the protein inserts into the membrane. The resulting ring-shaped pores and kinetically trapped arc-shaped assemblies are all seen to perforate the membrane, as also visible by the ejection of its lipids. Membrane insertion requires a concerted conformational change of the monomeric subunits, with a marked expansion in pore diameter due to large changes in subunit structure and packing.

  10. Composite Membrane Formation by Combination of Reaction-Induced and Nonsolvent-Induced Phase Separation

    KAUST Repository

    Aburabie, Jamaliah

    2017-05-25

    A novel method of preparing skinned asymmetric membranes with two distinctive layers is described: a top layer composed of chemically cross-linked polymer chains (dense layer) and a bottom layer of non-cross-linked polymer chains (porous substructure). The method consists of two simple steps that are compatible with industrial membrane fabrication facilities. Unlike conventional processes to prepare asymmetric membranes, with this approach it is possible to finely control the structure and functionalities of the final membrane. The thickness of the dense layer can be easily controlled over several orders of magnitude and targeted functional groups can be readily incorporated in it.

  11. CR2-mediated activation of the complement alternative pathway results in formation of membrane attack complexes on human B lymphocytes

    DEFF Research Database (Denmark)

    Nielsen, C H; Marquart, H V; Prodinger, W M;

    2001-01-01

    Normal human B lymphocytes activate the alternative pathway of complement via complement receptor type 2 (CR2, CD21), that binds hydrolysed C3 (iC3) and thereby promotes the formation of a membrane-bound C3 convertase. We have investigated whether this might lead to the generation of a C5...... convertase and consequent formation of membrane attack complexes (MAC). Deposition of C3 fragments and MAC was assessed on human peripheral B lymphocytes in the presence of 30% autologous serum containing 4.4 mM MgCl2/20 mM EGTA, which abrogates the classical pathway of complement without affecting...... the alternative pathway. Blockade of the CR2 ligand-binding site with the monoclonal antibody FE8 resulted in 56 +/- 13% and 71 +/- 9% inhibition of the C3-fragment and MAC deposition, respectively, whereas the monoclonal antibody HB135, directed against an irrelevant CR2 epitope, had no effect. Blockade...

  12. Pore formation in lipid membrane I: Continuous reversible trajectory from intact bilayer through hydrophobic defect to transversal pore.

    Science.gov (United States)

    Akimov, Sergey A; Volynsky, Pavel E; Galimzyanov, Timur R; Kuzmin, Peter I; Pavlov, Konstantin V; Batishchev, Oleg V

    2017-09-22

    Lipid membranes serve as effective barriers allowing cells to maintain internal composition differing from that of extracellular medium. Membrane permeation, both natural and artificial, can take place via appearance of transversal pores. The rearrangements of lipids leading to pore formation in the intact membrane are not yet understood in details. We applied continuum elasticity theory to obtain continuous trajectory of pore formation and closure, and analyzed molecular dynamics trajectories of pre-formed pore reseal. We hypothesized that a transversal pore is preceded by a hydrophobic defect: intermediate structure spanning through the membrane, the side walls of which are partially aligned by lipid tails. This prediction was confirmed by our molecular dynamics simulations. Conversion of the hydrophobic defect into the hydrophilic pore required surmounting some energy barrier. A metastable state was found for the hydrophilic pore at the radius of a few nanometers. The dependence of the energy on radius was approximately quadratic for hydrophobic defect and small hydrophilic pore, while for large radii it depended on the radius linearly. The pore energy related to its perimeter, line tension, thus depends of the pore radius. Calculated values of the line tension for large pores were in quantitative agreement with available experimental data.

  13. Line tension at lipid phase boundaries regulates formation of membrane vesicles in living cells

    DEFF Research Database (Denmark)

    Vind-Kezunovic, D.; Nielsen, C.H.; Wojewodzka, U.;

    2008-01-01

    fluorescein-labeled cholera toxin B subunit which labels ganglioside GM(1) enriched plasma membrane rafts. Cholesterol depletion with methyl-beta-cyclodextrin enhanced DiI vesiculation, GM(1)/DiI domain separation and was accompanied by a detachment of the subcortical cytoskeleton from the plasma membrane...

  14. Line tension at lipid phase boundaries regulates formation of membrane vesicles in living cells

    DEFF Research Database (Denmark)

    Vind-Kezunovic, Dina; Helix Nielsen, Claus; Wojewodzka, Urszula;

    2008-01-01

    -labeled cholera toxin B subunit which labels ganglioside GM(1) enriched plasma membrane rafts. Cholesterol depletion with methyl-beta-cyclodextrin enhanced DiI vesiculation, GM(1)/DiI domain separation and was accompanied by a detachment of the subcortical cytoskeleton from the plasma membrane. Based...

  15. Electrochemical characterization of pore formation by bacterial protein toxins on hybrid supported membranes.

    Science.gov (United States)

    Wilkop, Thomas; Xu, Danke; Cheng, Quan

    2008-05-20

    The interaction of pore-forming streptolysin O (SLO) with biomimetic lipid membranes has been studied by electrochemical methods. Phosphatidylcholine lipid vesicles were deposited onto gold electrodes modified with supporting layers of hexyl thioctate (HT) or thioctic acid tri(ethylene glycol) ester (TA-TEGE), and integrity and permeability of the resulting membranes were characterized by cyclic voltammetry and impedance spectroscopy. Both positively and negatively charged electrochemical probes, potassium ferrocyanide, hexaammineruthenium(III) chloride, and ferrocene carboxylic acid (FCA), were employed to evaluate their suitability to probe the membrane permeability properties, with FCA exhibiting ideal behavior and thus employed throughout the work. Fusion of vesicles incubated with SLO on the electrodes yielded membranes that showed a distinctive response pattern for FCA as a function of SLO concentration. A direct dependence of both the currents and peak separation of FCA in the cyclic voltammograms was observed over a concentration range of 0-10 hemolytic units (HU)/microL of the toxin. The interaction of SLO with preformed supported lipid membranes was also investigated, and much lower response was observed, suggesting a different extent of membrane-toxin interactions on such an interface. Nonionic surfactant Triton was found to disrupt the vesicle structure but could not completely remove a preformed membrane to fully restore the electrode response. The information reported here offers some unique insight into toxin-surface interactions on a hybrid membrane, facilitating the development of electrochemically based sensing platforms for detecting trace amounts of bacterial toxins via the perforation process.

  16. Trans-complex formation by proteolipid channels in the terminal phase of membrane fusion

    DEFF Research Database (Denmark)

    Peters, C; Bayer, M J; Bühler, S

    2001-01-01

    +/calmodulin controls this terminal process in many intracellular fusion events. Here we identify V0, the membrane-integral sector of the vacuolar H+-ATPase, as a target of calmodulin on yeast vacuoles. Between docking and bilayer fusion, V0 sectors from opposing membranes form complexes. V0 trans...

  17. Copper(II) enhances membrane-bound α-synuclein helix formation.

    Science.gov (United States)

    Lucas, Heather R; Lee, Jennifer C

    2011-03-01

    Interactions of copper and membranes with α-synuclein have been implicated in pathogenic mechanisms of Parkinson's disease, yet work examining both concurrently is scarce. We have examined the effect of copper(ii) on protein/vesicle binding and found that both the copper(ii) affinity and α-helical content are enhanced for the membrane-bound protein.

  18. Copper(II) enhances membrane-bound α-synuclein helix formation

    OpenAIRE

    Lucas, Heather R.; Lee, Jennifer C.

    2011-01-01

    Interactions of copper and membranes with α-synuclein have been implicated in pathogenic mechanisms of Parkinson’s disease, yet work examining both concurrently is scarce. We have examined the effect of copper(II) on protein/vesicle binding and found that both the copper(II) affinity and α-helical content are enhanced for the membrane-bound protein.

  19. The pathogenesis of rheumatoid arthritis in radiological studies. Part I: Formation of inflammatory infiltrates within the synovial membrane

    OpenAIRE

    Sudoł-Szopińska, Iwona; Kontny, Ewa; Maśliński, Włodzimierz; Prochorec-Sobieszek, Monika; Kwiatkowska, Brygida; Zaniewicz-Kaniewska, Katarzyna; Warczyńska, Agnieszka

    2012-01-01

    Rheumatoid arthritis is a chronic inflammatory disease with a multifactorial etiology and varied course, which in the majority of patients leads to partial disability or to permanent handicap. Its characteristic trait is a persistent inflammation of the synovial membrane and the formation of an invasive synovial tissue, called the pannus, which in time leads to destruction of the cartilage, subchondral bone tissue, and the soft tissue of the affected joint(s). The pathogenesis of rheumatoid a...

  20. Self-Assembly-Directed Aerogel and Membrane Formation from a Magnetic Composite: An Approach to Developing Multifunctional Materials.

    Science.gov (United States)

    Vivek, Balachandran; Prasad, Edamana

    2017-03-01

    Herein, we report the preparation of an aerogel and a membrane from a magnetic composite material by tuning the self-assembly at the molecular level. The gel exhibits an excellent oil absorption property, and the membrane shows a remarkable autonomous self-healing property. The composite is formed from an organosilicon-modified poly(amidoamine) (PAMAM) dendrimer, which is linked with iron oxide nanoparticles and poly(vinyl alcohol). Upon the addition of a cross-linker (formaldehyde), the system undergoes a fast self-assembly and gelation process. The aerogel, obtained after drying of the hydrogel, was modified with 1- bromohexadecane at room temperature and utilized for the removal of oil from water with 22.9 g/g absorption capacity. Intriguingly, the same system forms a membrane with 97% autonomous self-healing ability, in the absence of the cross-linker. The membrane was used to remove the salt content from water with an efficiency of 85%. The control experiments suggest that the presence of the magnetic material (iron oxide) plays a key role in the formation of both the aerogel and membrane.

  1. Is the T1ρ MRI profile of hyaline cartilage in the normal hip uniform?

    Science.gov (United States)

    Rakhra, Kawan S; Cárdenas-Blanco, Arturo; Melkus, Gerd; Schweitzer, Mark E; Cameron, Ian G; Beaulé, Paul E

    2015-04-01

    T1ρ MRI is an imaging technique sensitive to proteoglycan (PG) content of hyaline cartilage. However, normative T1ρ values have not been established for the weightbearing cartilage of the hip, and it is not known whether it is uniform or whether there is topographic variation. Knowledge of the T1ρ profile of hyaline cartilage in the normal hip is important for establishing a baseline against which comparisons can be made to experimental and clinical arthritic subjects. In this diagnostic study, we determined (1) the T1ρ MRI values of hyaline cartilage of the normal hip; and (2) whether the T1ρ MRI profile of the normal hip hyaline cartilage is uniform. Fourteen asymptomatic volunteers (11 men, three women; mean age, 35 years) prospectively underwent 1.5-T T1ρ MRI of a single hip. The weightbearing hyaline cartilage bilayer of the acetabulum and femoral head was evaluated on sagittal images and segmented into four zones: (1) anterior; (2) anterosuperior; (3) posterosuperior; and (4) and posterior. For the full region of interest and within each zone and each sagittal slice, we calculated the mean T1ρ relaxation value, a parameter that indirectly quantifies PG content, where T1ρ is inversely related to PG concentration. There was variation in the T1ρ relaxation values depending on zone (anterior to posterior) and slice (medial to lateral). When combining the most anterior quadrants (Zones 1 and 2), the T1ρ relaxation values were lower than those in the combined posterior quadrants (Zones 3 and 4) (30.4 msec versus 32.2 msec, respectively; p = 0.002), reflecting higher PG concentration. There was a difference between the T1ρ relaxation values of the sagittal slices (p = 0.038), most pronounced anteriorly in Zone 1 (26.6 msec, p = 0.001). With a selective combination of zones and slices, there were lower mean T1ρ values in the anterolateral-most region compared with the remainder of the weightbearing portion of the hip (28.6 msec versus 32.2 msec

  2. Involvement of cytoskeletal proteins in the barrier function of the human erythrocyte membrane. III. Permeability of spectrin-depleted inside-out membrane vesicles to hydrophilic nonelectrolytes. Formation of leaks by chemical or enzymatic modification of membrane proteins.

    Science.gov (United States)

    Klonk, S; Deuticke, B

    1992-04-29

    Spectrin-depleted inside-out vesicles (IOV's) prepared from human erythrocyte membranes were characterized in terms of size, ground permeability to hydrophilic nonelectrolytes and their sensitivity to modification by SH reagents, DIDS and trypsin. IOV's proved to have the same permeability of their lipid domain to erythritol as native erythrocytes, in contrast to resealed ghosts (Klonk, S. and Deuticke, B. (1992) Biochim. Biophys. Acta 1106, 126-136 (Part I in this series)), which have a residual leak. On the other hand, IOV's have a slightly elevated permeability for mannitol and sucrose, nonelectrolytes which are almost (mannitol) or fully (sucrose) impermeant in the native membrane. These increased fluxes, which have a high activation energy and can be stimulated by phloretin, are, however, also much smaller than the corresponding leak fluxes observed in resealed ghosts. In view of these differences, formation of IOV's can be concluded to go along with partial annealing of barrier defects persisting in the erythrocyte membrane after preparation of resealed ghosts. Oxidation of SH groups of the IOV membrane by diamide produces an enhancement of permeability for hydrophilic nonelectrolytes which is much less pronounced than that induced by a similar treatment of erythrocytes or ghosts (Klonk, S. and Deuticke, B. (1992) Biochim. Biophys. Acta 1106, 126-136 (Part I in this series)). Moreover, proteolytic treatment of the vesicle membrane, although leading to a marked digestion of integral membrane proteins, only induces a minor, saturating increase of permeability, much lower than that in trypsinized resealed ghosts (Klonk, S. and Deuticke, B. (1992) Biochim. Biophys. Acta 1106, 137-142 (Part II of this series)). Since absence of the cytoskeletal proteins, spectrin and actin, is the major difference between IOV's and resealed ghosts, these results may be taken as further evidence for a dependence of the barrier properties of the erythrocyte membrane bilayer domain

  3. Characterization of the ectodomain of the envelope protein of dengue virus type 4: expression, membrane association, secretion and particle formation in the absence of precursor membrane protein.

    Directory of Open Access Journals (Sweden)

    Szu-Chia Hsieh

    Full Text Available The envelope (E of dengue virus (DENV is the major target of neutralizing antibodies and vaccine development. After biosynthesis E protein forms a heterodimer with precursor membrane (prM protein. Recent reports of infection enhancement by anti-prM monoclonal antibodies (mAbs suggest anti-prM responses could be potentially harmful. Previously, we studied a series of C-terminal truncation constructs expressing DENV type 4 prM/E or E proteins and found the ectodomain of E protein alone could be recognized by all 12 mAbs tested, suggesting E protein ectodomain as a potential subunit immunogen without inducing anti-prM response. The characteristics of DENV E protein ectodomain in the absence of prM protein remains largely unknown.In this study, we investigated the expression, membrane association, glycosylation pattern, secretion and particle formation of E protein ectodomain of DENV4 in the presence or absence of prM protein. E protein ectodomain associated with membrane in or beyond trans-Golgi and contained primarily complex glycans, whereas full-length E protein associated with ER membrane and contained high mannose glycans. In the absence of prM protein, E protein ectodomain can secrete as well as form particles of approximately 49 nm in diameter, as revealed by sucrose gradient ultracentrifugation with or without detergent and electron microscopy. Mutational analysis revealed that the secretion of E protein ectodomain was affected by N-linked glycosylation and could be restored by treatment with ammonia chloride.Considering the enhancement of DENV infectivity by anti-prM antibodies, our findings provide new insights into the expression and secretion of E protein ectodomain in the absence of prM protein and contribute to future subunit vaccine design.

  4. Formation of polyhedral vesicles and polygonal membrane tubes induced by banana-shaped proteins

    Science.gov (United States)

    Noguchi, Hiroshi

    2015-12-01

    The shape transformations of fluid membranes induced by curved protein rods are studied using meshless membrane simulations. The rod assembly at low rod density induces a flat membrane tube and oblate vesicle. It is found that the polyhedral shapes are stabilized at high rod densities. The discrete shape transition between triangular and buckled discoidal tubes is obtained and their curvature energies are analyzed by a simple geometric model. For vesicles, triangular hosohedron and elliptic-disk shapes are formed in equilibrium, whereas tetrahedral and triangular prism shapes are obtained as metastable states.

  5. Deciphering chondrocyte behaviour in matrix-induced autologous chondrocyte implantation to undergo accurate cartilage repair with hyaline matrix.

    Science.gov (United States)

    Demoor, M; Maneix, L; Ollitrault, D; Legendre, F; Duval, E; Claus, S; Mallein-Gerin, F; Moslemi, S; Boumediene, K; Galera, P

    2012-06-01

    Since the emergence in the 1990s of the autologous chondrocytes transplantation (ACT) in the treatment of cartilage defects, the technique, corresponding initially to implantation of chondrocytes, previously isolated and amplified in vitro, under a periosteal membrane, has greatly evolved. Indeed, the first generations of ACT showed their limits, with in particular the dedifferentiation of chondrocytes during the monolayer culture, inducing the synthesis of fibroblastic collagens, notably type I collagen to the detriment of type II collagen. Beyond the clinical aspect with its encouraging results, new biological substitutes must be tested to obtain a hyaline neocartilage. Therefore, the use of differentiated chondrocytes phenotypically stabilized is essential for the success of ACT at medium and long-term. That is why researchers try now to develop more reliable culture techniques, using among others, new types of biomaterials and molecules known for their chondrogenic activity, giving rise to the 4th generation of ACT. Other sources of cells, being able to follow chondrogenesis program, are also studied. The success of the cartilage regenerative medicine is based on the phenotypic status of the chondrocyte and on one of its essential component of the cartilage, type II collagen, the expression of which should be supported without induction of type I collagen. The knowledge accumulated by the scientific community and the experience of the clinicians will certainly allow to relief this technological challenge, which influence besides, the validation of such biological substitutes by the sanitary authorities. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  6. Shiga toxin induces membrane reorganization and formation of long range lipid order

    DEFF Research Database (Denmark)

    Solovyeva, Vita; Johannes, Ludger; Simonsen, Adam Cohen

    2015-01-01

    microscopy. A content of 1% of glycosphingolipid globotriaosylceramide (Gb3) receptor lipids in a bilayer was used to bind the Shiga toxin B-subunit to the surface of gel domains. Binding of the Shiga toxin B-subunit to lipids led to the modulation of orientational membrane texture in gel domains and induced...... membrane reordering. When Shiga toxin was added above the lipid chain melting temperature, the toxin interaction with the membrane induced rearrangement and clustering of Gb3 lipids that resulted in the long range order and alignment of lipids in gel domains. The toxin induced redistribution of Gb3 lipids...... inside gel domains is governed by the temperature at which Shiga toxin was added to the membrane: above or below the phase transition. The temperature is thus one of the critical factors controlling lipid organization and texture in the presence of Shiga toxin. Lipid chain ordering imposed by Shiga toxin...

  7. Recycling endosomes in apical plasma membrane domain formation and epithelial cell polarity

    NARCIS (Netherlands)

    Golachowska, Magdalena R.; Hoekstra, Dick; van IJzendoorn, Sven C. D.

    2010-01-01

    Recycling endosomes have taken central stage in the intracellular sorting and polarized trafficking of apical and basolateral plasma membrane components. Molecular players in the underlying mechanisms are now emerging, including small GTPases, class V myosins and adaptor proteins. In particular,

  8. The Formation of Porous Membranes by Filtration of Aerosol Nano-particles

    DEFF Research Database (Denmark)

    Andersen, Sune Klint; Johannessen, Tue; Mosleh, Majid

    2002-01-01

    Flame-generated aerosol particles of Al2O3 were deposited by gas filtration on two types of porous and ceramic tubes of α-Al2O3 with mean pore diameters of 450 and 2700 nm, respectively. The particles were aggregates with average mobility diameters in the range of 30¨¢100 nm and primary particle...... nitrogen capillary condensation. The particles form a distinct, homogeneous membrane layer with a porosity of ∼90% on top of the substrate surface and only penetrate slightly into the substrate structure. The mean pore sizes of the deposited membranes determined by nitrogen condensation agree approximately...... membrane layer. This effect is particularly significant for the aerosol particles with the lowest mean size, probably due to particles deposited in the pore mouths of the substrate. The particles and the deposited membranes are X-ray amorphous but retain their specific surface area on heating to even high...

  9. Formation and fluidity measurement of supported lipid bilayer on polyvinyl chloride membrane

    Science.gov (United States)

    Kobayashi, Takuji; Kono, Akiteru; Futagawa, Masato; Sawada, Kazuaki; Tero, Ryugo

    2014-02-01

    We prepared an artificial lipid bilayer on a plasticized poly(vinyl chloride) (PVC) membrane on a Si3N4 layer deposited on a Si wafer. We optimized the experimental condition for the fabrication of the PVC membrane, and obtained a PVC membrane with a flat and uniform surface on the scale of several hundreds of micrometer suitable for a substrate for supported lipid bilayers (SLBs). The SLB of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) was formed on the PVC membrane by the vesicle fusion method. The observation with a conventional epi-fluorescence microscope and a confocal laser scanning microscope gave geometrically uniform images of the SLB on the PVC membrane. The fluidity and the mobile fraction of the SLB was evaluated by the fluorescence recovery after photobleaching method, and compared with that on a thermally oxidized SiO2/Si substrate. The SLB on the PVC membrane contained immobile fraction ˜30%, but the diffusion in the mobile fraction was two times faster than that in the SLB on SiO2/Si, which had little immobile fraction.

  10. Thermodynamics of Micelle Formation and Membrane Fusion Modulate Antimicrobial Lipopeptide Activity.

    Science.gov (United States)

    Lin, Dejun; Grossfield, Alan

    2015-08-18

    Antimicrobial lipopeptides (AMLPs) are antimicrobial drug candidates that preferentially target microbial membranes. One class of AMLPs, composed of cationic tetrapeptides attached to an acyl chain, have minimal inhibitory concentrations in the micromolar range against a range of bacteria and fungi. Previously, we used coarse-grained molecular dynamics simulations and free energy methods to study the thermodynamics of their interaction with membranes in their monomeric state. Here, we extended the study to the biologically relevant micellar state, using, to our knowledge, a novel reaction coordinate based on hydrophobic contacts. Using umbrella sampling along this reaction coordinate, we identified the critical transition states when micelles insert into membranes. The results indicate that the binding of these AMLP micelles to membranes is thermodynamically favorable, but in contrast to the monomeric case, there are significant free energy barriers. The height of these free energy barriers depends on the membrane composition, suggesting that the AMLPs' ability to selectively target bacterial membranes may be as much kinetic as thermodynamic. This mechanism highlights the importance of considering oligomeric state in solution as criterion when optimizing peptides or lipopeptides as antibiotic leads.

  11. Formation and fluidity measurement of supported lipid bilayer on polyvinyl chloride membrane

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Takuji, E-mail: kobayashi-t@int.ee.tut.ac.jp; Kono, Akiteru, E-mail: kobayashi-t@int.ee.tut.ac.jp; Sawada, Kazuaki [Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka Tempaku-cho, Toyohashi, 441-8580 (Japan); Futagawa, Masato [Department of Electrical and Electronic Information Engineering and Head Office for the Tailor-Made and Baton-Zone Graduate Course, Toyohashi University of Technology, 1-1 Hibarigaoka Tempaku-cho, Toyohashi, 441-8580 (Japan); Tero, Ryugo, E-mail: tero@tut.jp [Electronics-Inspired Interdisciplinary Research Institute and Department of Environmental and Life Sciences, Toyohashi University of Technology, 1-1 Hibarigaoka Tempaku-cho, Toyohashi, 441-8580 (Japan)

    2014-02-20

    We prepared an artificial lipid bilayer on a plasticized poly(vinyl chloride) (PVC) membrane on a Si3N4 layer deposited on a Si wafer. We optimized the experimental condition for the fabrication of the PVC membrane, and obtained a PVC membrane with a flat and uniform surface on the scale of several hundreds of micrometer suitable for a substrate for supported lipid bilayers (SLBs). The SLB of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) was formed on the PVC membrane by the vesicle fusion method. The observation with a conventional epi-fluorescence microscope and a confocal laser scanning microscope gave geometrically uniform images of the SLB on the PVC membrane. The fluidity and the mobile fraction of the SLB was evaluated by the fluorescence recovery after photobleaching method, and compared with that on a thermally oxidized SiO{sub 2}/Si substrate. The SLB on the PVC membrane contained immobile fraction ∼30%, but the diffusion in the mobile fraction was two times faster than that in the SLB on SiO{sub 2}/Si, which had little immobile fraction.

  12. Postnatal expression in hyaline cartilage of constitutively active human collagenase-3 (MMP-13) induces osteoarthritis in mice

    National Research Council Canada - National Science Library

    Neuhold, L A; Killar, L; Zhao, W; Sung, M L; Warner, L; Kulik, J; Turner, J; Wu, W; Billinghurst, C; Meijers, T; Poole, A R; Babij, P; DeGennaro, L J

    2001-01-01

    ...). We have used tetracycline-regulated transcription in conjunction with a cartilage-specific promoter to target a constitutively active human MMP-13 to the hyaline cartilages and joints of transgenic mice...

  13. Chitosan-glycerol phosphate/blood implants improve hyaline cartilage repair in ovine microfracture defects.

    Science.gov (United States)

    Hoemann, Caroline D; Hurtig, Mark; Rossomacha, Evgeny; Sun, Jun; Chevrier, Anik; Shive, Matthew S; Buschmann, Michael D

    2005-12-01

    Microfracture is a surgical procedure that is used to treat focal articular cartilage defects. Although joint function improves following microfracture, the procedure elicits incomplete repair. As blood clot formation in the microfracture defect is an essential initiating event in microfracture therapy, we hypothesized that the repair would be improved if the microfracture defect were filled with a blood clot that was stabilized by the incorporation of a thrombogenic and adhesive polymer, specifically, chitosan. The objectives of the present study were to evaluate (1) blood clot adhesion in fresh microfracture defects and (2) the quality of the repair, at six months postoperatively, of microfracture defects that had been treated with or without chitosan-glycerol phosphate/blood clot implants, using a sheep model. In eighteen sheep, two 1-cm2 full-thickness chondral defects were created in the distal part of the femur and treated with microfracture; one defect was made in the medial femoral condyle, and the other defect was made in the trochlea. In four sheep, microfracture defects were created bilaterally; the microfracture defects in one knee received no further treatment, and the microfracture defects in the contralateral knee were filled with chitosan-glycerol phosphate/autologous whole blood and the implants were allowed to solidify. Fresh defects in these four sheep were collected at one hour postoperatively to compare the retention of the chitosan-glycerol phosphate/blood clot with that of the normal clot and to define the histologic characteristics of these fresh defects. In the other fourteen sheep, microfracture defects were made in only one knee and either were left untreated (control group; six sheep) or were treated with chitosan-glycerol phosphate/blood implant (treatment group; eight sheep), and the quality of repair was assessed histologically, histomorphometrically, and biochemically at six months postoperatively. In the defects that were examined

  14. Synergy of Membrane Curvature-Stabilization and Electrostatic Interaction leads to Formation of Block Liposomes by Colossal Charged Lipids

    Science.gov (United States)

    Zidovska, Alexandra; Ewert, Kai K.; Safinya, Cyrus R.; Quispe, Joel; Carragher, Bridget; Potter, Clinton S.

    2008-03-01

    Recently, we have reported block liposomes (BLs), a new vesicle phase formed in mixtures of MVLBG2, DOPC and water (A. Zidovska et al., Submitted, 2007), where MVLBG2 is a newly synthesized highly charged (16+) lipid (K. Ewert et al., JACS, 2006) with giant dendrimer-like headgroup. BLs are liposomes consisting of distinctly shaped nanoscale spheres, pears, tubes, or rods connected into blocks. In this work we investigate the contribution of spontaneous curvature and membrane charge density to the formation of BLs. By comparing with a system of matching membrane charge density but zero spontaneous curvature and by screening the charge of MVLBG2 but keeping the curvature constant, we were able to identify both, spontaneous curvature and membrane charge, as critical parameters for BLs-formation. The effect of salt and pH on the shape evolution of the BLs was also carefully studied. Funding provided by DOE DE-FG-02-06ER46314, NIH GM-59288, NSF DMR-0503347.

  15. Dynamics of biofilm formation under different nutrient levels and the effect on biofouling of a reverse osmosis membrane system.

    Science.gov (United States)

    Chen, Xi; Suwarno, Stanislaus Raditya; Chong, Tzyy Haur; McDougald, Diane; Kjelleberg, Staffan; Cohen, Yehuda; Fane, Anthony G; Rice, Scott A

    2013-01-01

    Pseudomonas aeruginosa PAO1 wild type and a mucoid derivative (FRD1) which over produces alginate were used to foul reverse osmosis (RO) membranes. When operated at a constant flux, biofilm formation on the RO membrane resulted in a slow rise in transmembrane pressure (TMP) of 22% for the initial four days of operation, followed by a sharp increase of 159% over the following two days. The initial slow increase in TMP was probably due to the formation of a biofilm on the membrane surface, which then accelerated the rate of biofouling through the effect of concentration polarization. At later stages of operation, most of the bacterial biomass consisted of dead cells. The amount of extracellular polymeric substances appeared to correlate positively with the number of dead cells. The results indicate that prolonging the initial stage of slow TMP increase and avoiding the latter stage of accelerated TMP increase would provide a sustainable operation of the RO system. These results suggest that nutrient limitation could reduce biofilm accumulation and delay the increase in TMP.

  16. Vesicle Docking to the Spindle Pole Body Is Necessary to Recruit the Exocyst During Membrane Formation in Saccharomyces cerevisiae

    Science.gov (United States)

    Mathieson, Erin M.; Suda, Yasuyuki; Nickas, Mark; Snydsman, Brian; Davis, Trisha N.; Muller, Eric G. D.

    2010-01-01

    During meiosis II in Saccharomyces cerevisiae, the cytoplasmic face of the spindle pole body, referred to as the meiosis II outer plaque (MOP), is modified in both composition and structure to become the initiation site for de novo formation of a membrane called the prospore membrane. The MOP serves as a docking complex for precursor vesicles that are targeted to its surface. Using fluorescence resonance energy transfer analysis, the orientation of coiled-coil proteins within the MOP has been determined. The N-termini of two proteins, Mpc54p and Spo21p, were oriented toward the outer surface of the structure. Mutations in the N-terminus of Mpc54p resulted in a unique phenotype: precursor vesicles loosely tethered to the MOP but did not contact its surface. Thus, these mpc54 mutants separate the steps of vesicle association and docking. Using these mpc54 mutants, we determined that recruitment of the Rab GTPase Sec4p, as well as the exocyst components Sec3p and Sec8p, to the precursor vesicles requires vesicle docking to the MOP. This suggests that the MOP promotes membrane formation both by localization of precursor vesicles to a particular site and by recruitment of a second tethering complex, the exocyst, that stimulates downstream events of fusion. PMID:20826607

  17. Calcifying fibrous pseudotumor in association with hyaline vascular type Castleman′s disease

    Directory of Open Access Journals (Sweden)

    Azam Muhammad

    2009-10-01

    Full Text Available Calcifying fibrous pseudotumor is a recently described rare entity. It is considered as sclerosing end stage of inflammatory myofibroblastic tumor. An association with hyaline vascular type Castleman′s disease has also been described. We report a case of a 13-year-old boy who presented with pain in epigastrium. Computed tomography scan of abdomen revealed a circumscribed mass arising from the gastric wall along the greater curvature. Histology revealed a tumor composed of spindle cells present within the dense hyalinized collagenous tissue. Lymphoplasmacytic infiltrate was seen along with lymphoid follicles, dystrophic and ossifying calcification. Tumor cells were focally positive for alpha smooth muscle actin and negative for anaplastic lymphoma kinase protein.

  18. Visualization of the macroscopic structure of hyaline cartilage with MR imaging.

    Science.gov (United States)

    Goodwin, D W

    2001-12-01

    The extracellular matrix of any tissue, including hyaline cartilage, has a structure that allows it to meet the physical demands placed upon that tissue. Accordingly, the structure of hyaline cartilage is not uniform. There is considerable variation from one joint to the next and even within a particular joint surface, probably reflecting a joint-specific architecture. This structure has a strong influence on T(2) relaxation. The relationship between T2 and matrix curvature relative to the main magnetic field (B(0)) provides tissue contrast. Images obtained with adequate resolution can exploit this contrast and demonstrate the structure of cartilage. Magnetic resonance imaging is thus capable of providing a detailed description of the structure of joint surfaces, information that is difficult to obtain even with histologic techniques.

  19. MIXED HYALINE VASCULAR AND PLASMA CELL TYPE CASTLEMAN’S DISEASE: REPORT OF A CASE

    Directory of Open Access Journals (Sweden)

    F. Asgarani

    2006-05-01

    Full Text Available Castleman’s disease (angiofollicular lymphoid hyperplasia includes a heterogeneous group of lymphoproliferative disorders. The cause of this disease remains uncertain. There are two types of localized Castleman’s disease: the more common hyaline vascular and the plasma cell types. Mixed variant is an uncommon localized lesion in general population. The lesions can occur in any part of the body that contains lymphoid tissue, although seventy percent are found in the anterior mediastinum. We report a thirty years old boy with Castleman’s disease who presented with fever, anorexia, weight loss,sweating, anemia and abdominal mass. The histologic examination of the biopsy specimens revealed a mixed hyaline vascular and plasma cell type of Castleman’s disease.

  20. Endosome-to-Plasma Membrane Recycling of VEGFR2 Receptor Tyrosine Kinase Regulates Endothelial Function and Blood Vessel Formation.

    Science.gov (United States)

    Jopling, Helen M; Odell, Adam F; Pellet-Many, Caroline; Latham, Antony M; Frankel, Paul; Sivaprasadarao, Asipu; Walker, John H; Zachary, Ian C; Ponnambalam, Sreenivasan

    2014-04-29

    Rab GTPases are implicated in endosome-to-plasma membrane recycling, but how such membrane traffic regulators control vascular endothelial growth factor receptor 2 (VEGFR2/KDR) dynamics and function are not well understood. Here, we evaluated two different recycling Rab GTPases, Rab4a and Rab11a, in regulating endothelial VEGFR2 trafficking and signalling with implications for endothelial cell migration, proliferation and angiogenesis. In primary endothelial cells, VEGFR2 displays co-localisation with Rab4a, but not Rab11a GTPase, on early endosomes. Expression of a guanosine diphosphate (GDP)-bound Rab4a S22N mutant caused increased VEGFR2 accumulation in endosomes. TfR and VEGFR2 exhibited differences in endosome-to-plasma membrane recycling in the presence of chloroquine. Depletion of Rab4a, but not Rab11a, levels stimulated VEGF-A-dependent intracellular signalling. However, depletion of either Rab4a or Rab11a levels inhibited VEGF-A-stimulated endothelial cell migration. Interestingly, depletion of Rab4a levels stimulated VEGF-A-regulated endothelial cell proliferation. Rab4a and Rab11a were also both required for endothelial tubulogenesis. Evaluation of a transgenic zebrafish model showed that both Rab4 and Rab11a are functionally required for blood vessel formation and animal viability. Rab-dependent endosome-to-plasma membrane recycling of VEGFR2 is important for intracellular signalling, cell migration and proliferation during angiogenesis.

  1. Effect of toluene on Pseudomonas stutzeri ST-9 morphology - plasmolysis, cell size, and formation of outer membrane vesicles.

    Science.gov (United States)

    Michael, Esti; Nitzan, Yeshayahu; Langzam, Yakov; Luboshits, Galia; Cahan, Rivka

    2016-08-01

    Isolated toluene-degrading Pseudomonas stutzeri ST-9 bacteria were grown in a minimal medium containing toluene (100 mg·L(-1)) (MMT) or glucose (MMG) as the sole carbon source, with specific growth rates of 0.019 h(-1) and 0.042 h(-1), respectively. Scanning (SEM) as well as transmission (TEM) electron microscope analyses showed that the bacterial cells grown to mid-log phase in the presence of toluene possess a plasmolysis space. TEM analysis revealed that bacterial cells that were grown in MMT were surrounded by an additional "material" with small vesicles in between. Membrane integrity was analyzed by leakage of 260 nm absorbing material and demonstrated only 7% and 8% leakage from cultures grown in MMT compared with MMG. X-ray microanalysis showed a 4.3-fold increase in Mg and a 3-fold increase in P in cells grown in MMT compared with cells grown in MMG. Fluorescence-activated cell sorting (FACS) analysis indicated that the permeability of the membrane to propidium iodide was 12.6% and 19.6% when the cultures were grown in MMG and MMT, respectively. The bacterial cell length increased by 8.5% ± 0.1% and 17% ± 2%, as measured using SEM images and FACS analysis, respectively. The results obtained in this research show that the presence of toluene led to morphology changes, such as plasmolysis, cell size, and formation of outer membrane vesicles. However, it does not cause significant damage to membrane integrity.

  2. Enhanced membrane pore formation through high-affinity targeted antimicrobial peptides.

    Directory of Open Access Journals (Sweden)

    Christopher J Arnusch

    Full Text Available Many cationic antimicrobial peptides (AMPs target the unique lipid composition of the prokaryotic cell membrane. However, the micromolar activities common for these peptides are considered weak in comparison to nisin, which follows a targeted, pore-forming mode of action. Here we show that AMPs can be modified with a high-affinity targeting module, which enables membrane permeabilization at low concentration. Magainin 2 and a truncated peptide analog were conjugated to vancomycin using click chemistry, and could be directed towards specific membrane embedded receptors both in model membrane systems and whole cells. Compared with untargeted vesicles, a gain in permeabilization efficacy of two orders of magnitude was reached with large unilamellar vesicles that included lipid II, the target of vancomycin. The truncated vancomycin-peptide conjugate showed an increased activity against vancomycin resistant Enterococci, whereas the full-length conjugate was more active against a targeted eukaryotic cell model: lipid II containing erythrocytes. This study highlights that AMPs can be made more selective and more potent against biological membranes that contain structures that can be targeted.

  3. Formation of Mitochondrial Outer Membrane Derived Protrusions and Vesicles in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Akihiro Yamashita

    Full Text Available Mitochondria are dynamic organelles that have inner and outer membranes. In plants, the inner membrane has been well studied but relatively little is known about the outer membrane. Here we report that Arabidopsis cells have mitochondrial outer membrane-derived structures, some of which protrude from the main body of mitochondria (mitochondrial outer-membrane protrusions; MOPs, while others form vesicle-like structures without a matrix marker. The latter vesicle-like structures are similar to some mammalian MDVs (mitochondrial-derived vesicles. Live imaging demonstrated that a plant MDV budded off from the tip of a MOP. MDVs were also observed in the drp3a drp3b double mutant, indicating that they could be formed without the mitochondrial fission factors DRP3A and DRP3B. Double staining studies showed that the MDVs were not peroxisomes, endosomes, Golgi apparatus or trans-Golgi network (TGN. The numbers of MDVs and MOPs increased in senescent leaves and after dark treatment. Together, these results suggest that MDVs and MOPs are related to leaf senescence.

  4. Formation of Mitochondrial Outer Membrane Derived Protrusions and Vesicles in Arabidopsis thaliana.

    Science.gov (United States)

    Yamashita, Akihiro; Fujimoto, Masaru; Katayama, Kenta; Yamaoka, Shohei; Tsutsumi, Nobuhiro; Arimura, Shin-Ichi

    2016-01-01

    Mitochondria are dynamic organelles that have inner and outer membranes. In plants, the inner membrane has been well studied but relatively little is known about the outer membrane. Here we report that Arabidopsis cells have mitochondrial outer membrane-derived structures, some of which protrude from the main body of mitochondria (mitochondrial outer-membrane protrusions; MOPs), while others form vesicle-like structures without a matrix marker. The latter vesicle-like structures are similar to some mammalian MDVs (mitochondrial-derived vesicles). Live imaging demonstrated that a plant MDV budded off from the tip of a MOP. MDVs were also observed in the drp3a drp3b double mutant, indicating that they could be formed without the mitochondrial fission factors DRP3A and DRP3B. Double staining studies showed that the MDVs were not peroxisomes, endosomes, Golgi apparatus or trans-Golgi network (TGN). The numbers of MDVs and MOPs increased in senescent leaves and after dark treatment. Together, these results suggest that MDVs and MOPs are related to leaf senescence.

  5. PRESSURE DRIVEN CONDUCTING POLYMER MEMBRANES DERIVED FROM LAYER BY LAYER FORMATION AND CHARACTERIZATION: A REVIEW

    Directory of Open Access Journals (Sweden)

    IZZATI IZNI YUSOFF

    2016-08-01

    Full Text Available The layer-by-layer method is a technique used for the fabrication of ultra-thin defect free films which involves alternating sequential adsorption of polycations and polyanions, while conducting polymer is characterized by a conjugated structure of alternating single and double bonds. The use of layer-by-layer in producing a membrane for separation has received considerable interest due to its properties. However, the introduction of conducting polymer as a base membrane is relatively new. Therefore, in this review, we discuss in detail three types of LBL techniques (dip, spin and spray layer-by-layer along with their parameters. We will also summarize current developments on the characterization of modified membrane prepared using the layer-by-layer techniques in terms of morphology, physical and chemical properties, and separation performances.

  6. Electromediated formation of DNA complexes with cell membranes and its consequences for gene delivery

    CERN Document Server

    Escoffre, Jean-Michel; Favard, Cyril; Teissié, Justin; Dean, David S; Rols, Marie-Pierre

    2011-01-01

    Electroporation is a physical method to induce the uptake of therapeutic drugs and DNA, by eukaryotic cells and tissues. The phenomena behind electro-mediated membrane permeabilization to plasmid DNA have been shown to be significantly more complex than those for small molecules. Small molecules cross the permeabilized membrane by diffusion whereas plasmid DNA first interacts with the electropermeabilized part of the cell surface, forming localized aggregates. The dynamics of this process is still poorly understood because direct observations have been limited to scales of the order of seconds. Here, cells are electropermeabilized in the presence of plasmid DNA and monitored with a temporal resolution of 2 ms. This allows us to show that during the first pulse application, plasmid complexes, or aggregates, start to form at distinct sites on the cell membrane. FRAP measurements show that the positions of these sites are remarkably immobile during the application of further pluses. A theoretical model is propos...

  7. The casting and mechanism of formation of semi-permeable polymer membranes in a microgravity environment

    Science.gov (United States)

    Vera, I.

    The National Electric Company of Venezuela, C.A.D.A.F.E., is sponsoring the development of this experiment which represents Venezuela's first scientific experiment in space. The apparatus for the automatic casting of polymer thin films will be contained in NASA's payload No. G-559 of the Get Away Special program for a future orbital space flight in the U.S. Space Shuttle. Semi-permeable polymer membranes have important applications in a variety of fields, such as medecine, energy, and pharmaceuticals, and in general fluid separation processes such as reverse osmosis, ultra-filtration, and electro-dialysis. The casting of semi-permeable membranes in space will help to identify the roles of convection in determining the strucutre of these membranes.

  8. Castleman Disease of Hyaline Vascular Type in the Infrathyroidal Region: A Masquerader of Parathyroid Adenoma

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Kwon; Kwon, Sun Young [Dongsan Medical Center, Keimyung University School of Medicine, Daegu (Korea, Republic of)

    2013-03-15

    Castleman disease of the infrathyroidal region is extremely rare. We report both CT and sonographic findings of a case of infrathyroidal paratracheal Castleman disease of hyaline vascular type, which masquerades parathyroid adenoma, in a 48-year-old woman. We further provide its histological findings at sonographically guided core-needle biopsy (US-CNB) and excisional biopsy. The lesion was ovoid with homogeneous intense enhancement on contrast-enhanced CT (CECT), and was homogeneous, markedly hypoechoic, and hypervascular on ultrasonography (US). Histological findings of the specimen obtained by US-CNB suggested lymphoproliferative lesion, and thus was inconclusive; those obtained by excisional biopsy were characteristics of Castleman disease of hyaline vascular type. Hyaline vascular type Castleman's disease should be included in the differential diagnosis of a mass of the infrathyroidal region with homogeneous intense enhancement on CECT, as well as with marked hypoechogenicity and hypervascularity on US. US-CNB may be of limited value in the histological diagnosis of this entity.

  9. Elastic cartilage reconstruction by transplantation of cultured hyaline cartilage-derived chondrocytes.

    Science.gov (United States)

    Mizuno, M; Takebe, T; Kobayashi, S; Kimura, S; Masutani, M; Lee, S; Jo, Y H; Lee, J I; Taniguchi, H

    2014-05-01

    Current surgical intervention of craniofacial defects caused by injuries or abnormalities uses reconstructive materials, such as autologous cartilage grafts. Transplantation of autologous tissues, however, places a significant invasiveness on patients, and many efforts have been made for establishing an alternative graft. Recently, we and others have shown the potential use of reconstructed elastic cartilage from ear-derived chondrocytes or progenitors with the unique elastic properties. Here, we examined the differentiation potential of canine joint cartilage-derived chondrocytes into elastic cartilage for expanding the cell sources, such as hyaline cartilage. Articular chondrocytes are isolated from canine joint, cultivated, and compared regarding characteristic differences with auricular chondrocytes, including proliferation rates, gene expression, extracellular matrix production, and cartilage reconstruction capability after transplantation. Canine articular chondrocytes proliferated less robustly than auricular chondrocytes, but there was no significant difference in the amount of sulfated glycosaminoglycan produced from redifferentiated chondrocytes. Furthermore, in vitro expanded and redifferentiated articular chondrocytes have been shown to reconstruct elastic cartilage on transplantation that has histologic characteristics distinct from hyaline cartilage. Taken together, cultured hyaline cartilage-derived chondrocytes are a possible cell source for elastic cartilage reconstruction. Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.

  10. Hyalinizing trabecular tumor of the thyroid gland: A puzzling entity on fine needle aspiration cytology

    Directory of Open Access Journals (Sweden)

    Jitendra Nasit

    2014-01-01

    Full Text Available Hyalinizing trabecular tumor (HTT is a rare unique but controversial thyroid neoplasm, characterized by prominent trabecular growth pattern and stromal hyalinization. Whether HTT is a benign tumor or a variant of papillary thyroid carcinoma (PTC is still unclear. Cytology findings of HTT have been described in few reports. Cytological features of HTT frequently overlap with those of PTC and medullary thyroid carcinoma, which can lead to frequent misdiagnosis. In order to avoid overtreatment like total thyroidectomy, pathologist should be aware of cytological features of HTT. We present a case of 35-year-old female with a right-side thyroid swelling for three years. Fine needle aspiration cytology was performed. According to The Bethesda System for Reporting Thyroid Cytopathology, cytological diagnosis of benign thyroid neoplasm was made. Histopathology of the right thyroidectomy specimen showed HTT. Accurate preoperative diagnosis of HTT requires a very meticulous and cautious approach in the evaluation of cytological features. Trabecular pattern of cells, vague curved nuclear palisading, radiating arrangement of cells around hyaline material, spindled to elongated cells, filamentous cytoplasmic processes with ill-defined cell border and yellow bodies are important diagnostic features of HTT. Nuclear features alone are insufficient for the diagnosis of HTT. Any suspicious cytology of thyroid lesion should follow hemithyroidectomy and histopathological evaluation.

  11. Uninduced adipose-derived stem cells repair the defect of full-thickness hyaline cartilage

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hai-ning; LI Lei; LENG Ping; WANG Ying-zhen; Lü Cheng-yu

    2009-01-01

    Objective: To testify the effect of the stem cells derived from the widely distributed fat tissue on repairing full-thickness hyaline cartilage defects.Methods: Adipose-derived stem cells (ADSCs) were derived from adipose tissue and cultured in vitro.Twentyseven New Zealand white rabbits were divided into three groups randomly.The cultured ADSCs mixed with calcium alginate gel were used to fill the full-thickness hyaline cartilage defects created at the patellafemoral joint,and the defects repaired with gel or without treatment served as control groups.After 4,8 and 12 weeks,the reconstructed tissue was evaluated macroscopically and microscopically.Histological analysis and qualitative scoring were also performed to detect the outcome.Results: Full thickness hyaline cartilage defects were repaired completely with ADSCs-derived dssue.The result was better in ADSCs group than the control ones.The microstructure of reconstructed tissue with ADSCs was similar to that of hvaline cartilage and contained more cells and regular matrix fibers,being better than other groups.Plenty of collagen fibers around cells could be seen under transmission electron microscopy.Statistical analysis revealed a significant difference in comparison with other groups at each time point(t=4.360,P<0.01).Conclusion: Thcse results indicate that stem cells derived from mature adipose without induction possess the ability to repair cartilage defects

  12. FORMATION AND MICROSTRUCTURE OF POLYETHYLENE MICROPOROUS MEMBRANES THROUGH THERMALLY INDUCED PHASE SEPARATION

    Institute of Scientific and Technical Information of China (English)

    LI Wenjun; YUAN Youxin; CABASSO,Israel

    1995-01-01

    Microporous membranes of low-high density polyethylene and their blends were prepared by thermally-induced phase separation of polymer/long-aliphatic chain alcohol (diluent)mixtures.The microstructures of this particular membrane, which depends on the diluent properties,polymer concentration and cooling rate, were observed by scanning electron microscopy."Beehive-type,"leafy-like, and lacy porous structure morphologies can be formed,depending on the blend composition and phase separation conditions, which were discussed by the polymer and diluent crystallization processes.

  13. Instantaneous carbon-carbon bond formation using a microchannel reactor with a catalytic membrane.

    Science.gov (United States)

    Uozumi, Yasuhiro; Yamada, Yoichi M A; Beppu, Tomohiko; Fukuyama, Naoshi; Ueno, Masaharu; Kitamori, Takehiko

    2006-12-20

    Instantaneous catalytic carbon-carbon bond forming reactions were achieved in a microchannel reactor having a polymeric palladium complex membrane. The catalytic membrane was constructed inside the microchannel via self-assembling complexation at the interface between the organic and aqueous phases flowing laminarly, where non-cross-linked polymer-bound phosphine and ammonium tetrachloropalladate dissolved, respectively. A palladium-catalyzed coupling reaction of aryl halides and arylboronic acids was performed using the microchannel reactor to give quantitative yields of biaryls within 4 s of retention time in the defined channel region.

  14. Requirements for the Formation of Membrane Pores by the Reovirus Myristoylated μ1N Peptide▿

    OpenAIRE

    Zhang, Lan; Agosto, Melina A.; Ivanovic, Tijana; King, David S.; Nibert, Max L.; Harrison, Stephen C.

    2009-01-01

    The outer capsid of the nonenveloped mammalian reovirus contains 200 trimers of the μ1 protein, each complexed with three copies of the protector protein σ3. Conformational changes in μ1 following the proteolytic removal of σ3 lead to release of the myristoylated N-terminal cleavage fragment μ1N and ultimately to membrane penetration. The μ1N fragment forms pores in red blood cell (RBC) membranes. In this report, we describe the interaction of recombinant μ1 trimers and synthetic μ1N peptides...

  15. Evidence for the involvement of lipid rafts localized at the ER-mitochondria associated membranes in autophagosome formation.

    Science.gov (United States)

    Garofalo, Tina; Matarrese, Paola; Manganelli, Valeria; Marconi, Matteo; Tinari, Antonella; Gambardella, Lucrezia; Faggioni, Alberto; Misasi, Roberta; Sorice, Maurizio; Malorni, Walter

    2016-06-01

    Mitochondria-associated membranes (MAMs) are subdomains of the endoplasmic reticulum (ER) that interact with mitochondria. This membrane scrambling between ER and mitochondria appears to play a critical role in the earliest steps of autophagy. Recently, lipid microdomains, i.e. lipid rafts, have been identified as further actors of the autophagic process. In the present work, a series of biochemical and molecular analyses has been carried out in human fibroblasts with the specific aim of characterizing lipid rafts in MAMs and to decipher their possible implication in the autophagosome formation. In fact, the presence of lipid microdomains in MAMs has been detected and, in these structures, a molecular interaction of the ganglioside GD3, a paradigmatic "brick" of lipid rafts, with core-initiator proteins of autophagy, such as AMBRA1 and WIPI1, was revealed. This association seems thus to take place in the early phases of autophagic process in which MAMs have been hypothesized to play a key role. The functional activity of GD3 was suggested by the experiments carried out by knocking down ST8SIA1 gene expression, i.e., the synthase that leads to the ganglioside formation. This experimental condition results in fact in the impairment of the ER-mitochondria crosstalk and the subsequent hindering of autophagosome nucleation. We thus hypothesize that MAM raft-like microdomains could be pivotal in the initial organelle scrambling activity that finally leads to the formation of autophagosome.

  16. Complex formation between primycin and ergosterol: entropy-driven initiation of modification of the fungal plasma membrane structure.

    Science.gov (United States)

    Virág, Eszter; Pesti, Miklós; Kunsági-Máté, Sándor

    2012-04-01

    The interaction of the antibiotic primycin with the main fungal sterol, ergosterol, was investigated in vitro in order to monitor the effect of primycin on the fungal plasma membrane at the molecular level. The thermodynamic parameters of complex formation were determined by measuring Rayleigh scattering as a signal sensitive to particle size. The Benesi-Hildebrand method validated the 1 : 1 stoichiometry of the primycin-ergosterol complexes. A very low enthalpy change (ΔH=-1.14 kJ mol(-1)) was measured during the complex formation, which itself cannot be responsible for the molecular association. However, the entropy production (ΔS=29.78 J mol K(-1)) observed during the complex formation can describe the molecular interaction. This effect is probably due to the partial destruction of the solvation shell of the interacting species before the interlinking of the molecules. The results highlight the importance of ergosterol as concerns the mode of effect of primycin in the treatment of fungal infections. As the entropy has a determinant role in the ergosterol-primycin interaction, this interaction exhibits a very high temperature dependence, with the important consequence that the effect exerted by primycin on the cell membranes increases with rising temperature, and the effect is therefore pronounced in fevered bodies.

  17. Effect of Extracellular Matrix Membrane on Bone Formation in a Rabbit Tibial Defect Model

    Directory of Open Access Journals (Sweden)

    Jin Wook Hwang

    2016-01-01

    Full Text Available Absorbable extracellular matrix (ECM membrane has recently been used as a barrier membrane (BM in guided tissue regeneration (GTR and guided bone regeneration (GBR. Absorbable BMs are mostly based on collagen, which is more biocompatible than synthetic materials. However, implanted absorbable BMs can be rapidly degraded by enzymes in vivo. In a previous study, to delay degradation time, collagen fibers were treated with cross-linking agents. These compounds prevented the enzymatic degradation of BMs. However, cross-linked BMs can exhibit delayed tissue integration. In addition, the remaining cross-linker could induce inflammation. Here, we attempted to overcome these problems using a natural ECM membrane. The membrane consisted of freshly harvested porcine pericardium that was stripped from cells and immunoreagents by a cleaning process. Acellular porcine pericardium (APP showed a bilayer structure with a smooth upper surface and a significantly coarser bottom layer. APP is an ECM with a thin layer (0.18–0.35 mm but with excellent mechanical properties. Tensile strength of APP was 14.15±2.24 MPa. In in vivo experiments, APP was transplanted into rabbit tibia. The biocompatible material was retained for up to 3 months without the need for cross-linking. Therefore, we conclude that APP could support osteogenesis as a BM for up to 3 months.

  18. In situ formation of leak-free polyethylene glycol (PEG) membranes in microfluidic fuel cells.

    Science.gov (United States)

    Ho, W F; Lim, K M; Yang, K-L

    2016-11-29

    Membraneless microfluidic fuel cells operated under two co-laminar flows often face serious fuel cross-over problems, especially when flow rates are close to zero. In this study, we show that polyethylene glycol (PEG) monomers can be cross-linked inside microfluidic channels to form leak-free PEG membranes, which prevent mixing of two incompatible electrolyte solutions while allowing diffusion of certain molecules (e.g. glucose) and ions. By using PEG monomers of different molecular weights and cross-linking conditions, we are able to tailor selectivity of the membrane to allow passage of glucose while blocking larger molecules such as trypan blue. As a proof of principle, a microfluidic fuel cell with a PEG membrane and two incompatible electrolytes (acid and base) is demonstrated. Thanks to the leak-free nature of the PEG membrane, these two electrolytes do not mix together even at very slow flow rates. This microfluidic fuel cell is able to generate a voltage up to ∼450 mV from 10 mM of glucose with a flow rate of 20 μL min(-1). This microfluidic fuel cell is potentially useful as a miniature power source for many applications.

  19. The mechanism of formation of microporous or skinned membranes produced by immersion precipitation

    NARCIS (Netherlands)

    Wijmans, J.G.; Baaij, J.P.B.; Smolders, C.A.

    1983-01-01

    Cellulose acetate and polysulfone casting solutions were coagulated in water/solvent mixtures with differing solvent content. Precipitation in pure water yielded skinned membranes. Precipitation in water/solvent mixtures with solvent concentration exceeding a certain minimum value (which is differen

  20. Role of transmembrane pH gradient and membrane binding in nisin pore formation

    NARCIS (Netherlands)

    Moll, Gert N.; Clark, Jonathan; Chan, Weng C.; Bycroft, Barrie W.; Roberts, Gordon C.K.; Konings, Wil N.; Driessen, Arnold J.M.

    1997-01-01

    Nisin is a cationic antimicrobial peptide that belongs to the group of lantibiotics. It is thought to form oligomeric pores in the target membrane by a mechanism that requires the transmembrane electrical potential (Delta psi) and that involves local pertubation of the lipid bilayer structure. Here

  1. Growth of silicone-immobilized bacteria on polycarbonate membrane filters, a technique to study microcolony formation under anaerobic conditions

    DEFF Research Database (Denmark)

    Højberg, Ole; Binnerup, S. J.; Sørensen, Jan

    1997-01-01

    A technique was developed to study microcolony formation by silicone- immobilized bacteria on polycarbonate membrane filters under anaerobic conditions. A sudden shift to anaerobiosis was obtained by submerging the filters in medium which was depleted for oxygen by a pure culture of bacteria....... The technique was used to demonstrate that preinduction of nitrate reductase under low-oxygen conditions was necessary for nonfermenting, nitrate-respiring bacteria, e.g., Pseudomonas spp., to cope with a sudden lack of oxygen. In contrast, nitrate-respiring, fermenting bacteria, e.g., Bacillus and Escherichia...

  2. Antiviral Innate Immune Response Interferes with the Formation of Replication-Associated Membrane Structures Induced by a Positive-Strand RNA Virus

    Directory of Open Access Journals (Sweden)

    Diede Oudshoorn

    2016-12-01

    Full Text Available Infection with nidoviruses like corona- and arteriviruses induces a reticulovesicular network of interconnected endoplasmic reticulum (ER-derived double-membrane vesicles (DMVs and other membrane structures. This network is thought to accommodate the viral replication machinery and protect it from innate immune detection. We hypothesized that the innate immune response has tools to counteract the formation of these virus-induced replication organelles in order to inhibit virus replication. Here we have investigated the effect of type I interferon (IFN treatment on the formation of arterivirus-induced membrane structures. Our approach involved ectopic expression of arterivirus nonstructural proteins nsp2 and nsp3, which induce DMV formation in the absence of other viral triggers of the interferon response, such as replicating viral RNA. Thus, this setup can be used to identify immune effectors that specifically target the (formation of virus-induced membrane structures. Using large-scale electron microscopy mosaic maps, we found that IFN-β treatment significantly reduced the formation of the membrane structures. Strikingly, we also observed abundant stretches of double-membrane sheets (a proposed intermediate of DMV formation in IFN-β-treated samples, suggesting the disruption of DMV biogenesis. Three interferon-stimulated gene products, two of which have been reported to target the hepatitis C virus replication structures, were tested for their possible involvement, but none of them affected membrane structure formation. Our study reveals the existence of a previously unknown innate immune mechanism that antagonizes the viral hijacking of host membranes. It also provides a solid basis for further research into the poorly understood interactions between the innate immune system and virus-induced replication structures.

  3. Colonization of a Central Venous Catheter by the Hyaline Fungus Fusarium solani Species Complex: A Case Report and SEM Imaging

    Directory of Open Access Journals (Sweden)

    Alberto Colombo

    2013-01-01

    Full Text Available The incidence of opportunistic infections by filamentous fungi is increasing partly due to the widespread use of central venous catheters (CVC, indwelling medical devices, and antineoplastic/immunosuppressive drugs. The case of a 13-year-old boy under treatment for acute lymphoblastic leukemia is presented. The boy was readmitted to the Pediatric Ward for intermittent fever of unknown origin. Results of blood cultures drawn from peripheral venous sites or through the CVC were compared. CVC-derived bottles (but not those from peripheral veins yielded hyaline fungi that, based on morphology, were identified as belonging to the Fusarium solani species complex. Gene amplification and direct sequencing of the fungal ITS1 rRNA region and the EF-1alpha gene confirmed the isolate as belonging to the Fusarium solani species complex. Portions of the CVC were analyzed by scanning electron microscopy. Fungi mycelia with long protruding hyphae were seen into the lumen. The firm adhesion of the fungal formation to the inner surface of the catheter was evident. In the absence of systemic infection, catheter removal and prophylactic voriconazole therapy were followed by disappearance of febrile events and recovery. Thus, indwelling catheters are prone to contamination by environmental fungi.

  4. In vivo cluster formation of nisin and Lipid II is correlated with membrane depolarization

    NARCIS (Netherlands)

    Tol, Menno B; Angeles, Danae Morales; Scheffers, Dirk-Jan

    2015-01-01

    Nisin and related lantibiotics kill bacteria by pore formation, or by sequestering Lipid II. Some lantibiotics sequester Lipid II into clusters, which were suggested to kill cells through delocalized peptidoglycan synthesis. Here, we show that cluster formation is always concomitant with (i)

  5. Effects of an elastic membrane on tube waves in permeable formations

    Energy Technology Data Exchange (ETDEWEB)

    Liu, H.; Johnson, D.

    1996-10-01

    In this paper, the modified properties were calculated for tube wave propagation in a fluid-filled borehole penetrating a permeable rock due to the presence of a mudcake which forms on the borehole wall. The mudcake was characterized by an impermeable elastic layer. The mudcake partial sealing mechanism was simulated using a finite membrane stiffness. Consequently, it was shown that the mudcake can reduce, but not eliminate, the permeability effects on the tube wave slowness and attenuation. Moreover, this paper discusses a variety of values for the relevant parameters especially the mudcake thickness and membrane stiffness. The important combinations of mudcake parameters were clarified by using an analytic expression for the low-frequency limit.

  6. Oxidation of Membrane Curvature-Regulating Phosphatidylethanolamine Lipid Results in Formation of Bilayer and Cubic Structures.

    Science.gov (United States)

    Sankhagowit, Shalene; Lee, Ernest Y; Wong, Gerard C L; Malmstadt, Noah

    2016-03-15

    Oxidation is associated with conditions related to chronic inflammations and aging. Cubic structures have been observed in the smooth endoplasmic reticulum and mitochondrial membranes of cells under oxidative stress (e.g., tumor cells and virus-infected cells). It has been previously suspected that oxidation can result in the rearrangement of lipids from a fluid lamellar phase to a cubic structure in organelles containing membranes enriched with amphiphiles that have nonzero intrinsic curvature, such as phosphatidylethanolamine (PE) and cardiolipin. This study focuses on the oxidation of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), a lipid that natively forms an inverted hexagonal phase at physiological conditions. The oxidized samples contain an approximately 3:2 molar ratio of nonoxidized to oxidized DOPE. Optical microscopy images collected during the hydration of this mixture from a dried film suggest that the system evolves into a coexistence of a stable fluid lamellar phase and transient square lattice structures with unit cell sizes of 500-600 nm. Small-angle X-ray scattering of the same lipid mixture yielded a body-centered Im3m cubic phase with the lattice parameter of 14.04 nm. On average, the effective packing parameter of the oxidized DOPE species was estimated to be 0.657 ± 0.069 (standard deviation). This suggests that the oxidation of PE leads to a group of species with inverted molecular intrinsic curvature. Oxidation can create amphiphilic subpopulations that potently impact the integrity of the membrane, since negative Gaussian curvature intrinsic to cubic phases can enable membrane destabilization processes.

  7. Evaluation of Zosteric Acid for Mitigating Biofilm Formation of Pseudomonas putida Isolated from a Membrane Bioreactor System

    Directory of Open Access Journals (Sweden)

    Andrea Polo

    2014-05-01

    Full Text Available This study provides data to define an efficient biocide-free strategy based on zosteric acid to counteract biofilm formation on the membranes of submerged bioreactor system plants. 16S rRNA gene phylogenetic analysis showed that gammaproteobacteria was the prevalent taxa on fouled membranes of an Italian wastewater plant. Pseudomonas was the prevalent genus among the cultivable membrane-fouler bacteria and Pseudomonas putida was selected as the target microorganism to test the efficacy of the antifoulant. Zosteric acid was not a source of carbon and energy for P. putida cells and, at 200 mg/L, it caused a reduction of bacterial coverage by 80%. Biofilm experiments confirmed the compound caused a significant decrease in biomass (−97% and thickness (−50%, and it induced a migration activity of the peritrichous flagellated P. putida over the polycarbonate surface not amenable to a biofilm phenotype. The low octanol-water partitioning coefficient and the high water solubility suggested a low bioaccumulation potential and the water compartment as its main environmental recipient and capacitor. Preliminary ecotoxicological tests did not highlight direct toxicity effects toward Daphnia magna. For green algae Pseudokirchneriella subcapitata an effect was observed at concentrations above 100 mg/L with a significant growth of protozoa that may be connected to a concurrent algal growth inhibition.

  8. Evaluation of Zosteric Acid for Mitigating Biofilm Formation of Pseudomonas putida Isolated from a Membrane Bioreactor System

    Science.gov (United States)

    Polo, Andrea; Foladori, Paola; Ponti, Benedetta; Bettinetti, Roberta; Gambino, Michela; Villa, Federica; Cappitelli, Francesca

    2014-01-01

    This study provides data to define an efficient biocide-free strategy based on zosteric acid to counteract biofilm formation on the membranes of submerged bioreactor system plants. 16S rRNA gene phylogenetic analysis showed that gammaproteobacteria was the prevalent taxa on fouled membranes of an Italian wastewater plant. Pseudomonas was the prevalent genus among the cultivable membrane-fouler bacteria and Pseudomonas putida was selected as the target microorganism to test the efficacy of the antifoulant. Zosteric acid was not a source of carbon and energy for P. putida cells and, at 200 mg/L, it caused a reduction of bacterial coverage by 80%. Biofilm experiments confirmed the compound caused a significant decrease in biomass (−97%) and thickness (−50%), and it induced a migration activity of the peritrichous flagellated P. putida over the polycarbonate surface not amenable to a biofilm phenotype. The low octanol-water partitioning coefficient and the high water solubility suggested a low bioaccumulation potential and the water compartment as its main environmental recipient and capacitor. Preliminary ecotoxicological tests did not highlight direct toxicity effects toward Daphnia magna. For green algae Pseudokirchneriella subcapitata an effect was observed at concentrations above 100 mg/L with a significant growth of protozoa that may be connected to a concurrent algal growth inhibition. PMID:24879523

  9. In-situ assessment of biofilm formation in submerged membrane system using optical coherence tomography and computational fluid dynamics

    KAUST Repository

    Fortunato, Luca

    2016-09-09

    This paper introduces a novel approach to study the biofouling development on gravity driven submerged membrane bioreactor (SMBR). The on-line monitoring of biofilm formation on a flat sheet membrane was conducted non-destructively using optical coherence tomography (OCT), allowing the in-situ investigation of the biofilm structure for 43 d. The OCT enabled to obtain a time-lapse of biofilm development on the membrane under the continuous operation. Acquired real-time information on the biofilm structure related to the change in the flux profile confirming the successful monitoring of the dynamic evolution of the biofouling layer. Four different phases were observed linking the permeate flux with the change of biofilm morphology. In particular, a stable flux of 2.1±0.1 L/m2 h was achieved with the achievement of steady biofilm morphology after 30 d of operation. Biofilm descriptors, such as thickness, biofilm area, macro-porosity and roughness (absolute and relative), were calculated for each OCT acquired scans. Interestingly, relative roughness was correlated with the flux decrease. Furthermore, the precise biofilm morphology obtained from the OCT scans was used in computational fluid dynamics (CFD) simulation to better understand the role of biofilm structure on the filtration mechanism. © 2016 Elsevier B.V.

  10. Docosapentaenoic acid (DPA) is a critical determinant of cubic membrane formation in amoeba Chaos mitochondria.

    Science.gov (United States)

    Deng, Yuru; Almsherqi, Zakaria A; Shui, Guanghou; Wenk, Markus R; Kohlwein, Sepp D

    2009-09-01

    Very long-chain polyunsaturated fatty acids (VLC-PUFAs), such as docosahexaenoic acid (DHA) and docosapentaenoic acid (DPA), have recently made it to the realm of "magical molecules" based on their multiple presumably beneficial effects in biological systems, making these PUFAs particularly interesting in biomedicine. Their specific biological functions, however, remain enigmatic. Here we provide evidence derived from studies in the amoeba Chaos that indicates a structural role for omega-6 DPA in cell membrane organization, which may help to explain the multiple diverse effects of VLC-PUFA in healthy and diseased states. Amoeba Chaos mitochondria undergo a remarkable and reversible morphological transition into cubic morphology on starvation. This morphological transition is reflected in major changes in fatty acid and lipid composition, as determined by gas liquid chromatography and mass spectrometry, in particular by a drastic increase in C22:5 modified phosphatidylcholine plasmalogen, phosphatidylethanolamine plasmalogen, and phosphatidylinositol species. Liposomes produced in vitro from lipids of starved amoeba cells show a high propensity to form hexagonal tubular and cubic morphologies. Addition of omega-6 DPA, but not of omega-3 DPA, to the cell culture also induced mitochondrial membrane transformation into cubic morphology in fed cells, demonstrating for the first time an important structural role of omega-6 DPA-containing lipids in cell membrane organization.

  11. Two-component membrane material properties and domain formation from dissipative particle dynamics.

    Science.gov (United States)

    Illya, G; Lipowsky, R; Shillcock, J C

    2006-09-21

    The material parameters (area stretch modulus and bending rigidity) of two-component amphiphilic membranes are determined from dissipative particle dynamics simulations. The preferred area per molecule for each species is varied so as to produce homogeneous mixtures or nonhomogeneous mixtures that form domains. If the latter mixtures are composed of amphiphiles with the same tail length, but different preferred areas per molecule, their material parameters increase monotonically as a function of composition. By contrast, mixtures of amphiphiles that differ in both tail length and preferred area per molecule form both homogeneous and nonhomogeneous mixtures that both exhibit smaller values of their material properties compared to the corresponding pure systems. When the same nonhomogeneous mixtures of amphiphiles are assembled into planar membrane patches and vesicles, the resulting domain shapes are different when the bending rigidities of the domains are sufficiently different. Additionally, both bilayer and monolayer domains are observed in vesicles. We conclude that the evolution of the domain shapes is influenced by the high curvature of the vesicles in the simulation, a result that may be relevant for biological vesicle membranes.

  12. Syringotoxin pore formation and inactivation in human red blood cell and model bilayer lipid membranes.

    Science.gov (United States)

    Szabó, Zsófia; Gróf, Pál; Schagina, Ludmila V; Gurnev, Philip A; Takemoto, Jon Y; Mátyus, Edit; Blaskó, Katalin

    2002-12-23

    The effect of syringotoxin (ST), a member of the cyclic lipodepsipeptides family (CLPs) produced by Pseudomonas syringae pv. syringae on the membrane permeability of human red blood cells (RBCs) and model bilayer lipid membranes (BLMs) was studied and compared to that of two recently investigated CLPs, syringomycin E (SRE) and syringopeptin 22A (SP22A) [Biochim. Biophys. Acta 1466 (2000) 79 and Bioelectrochemistry 52 (2000) 161]. The permeability-increasing effect of ST on RBCs was the least among the three CLPs. A time-dependent ST pore inactivation was observed on RBCs at 20 and 37 degrees C but not at 8 degrees C. From the kinetic model worked out parameters as permeability coefficient of RBC membrane for 86Rb(+) and pores mean lifetime were calculated. A shorter pores mean lifetime was calculated at 37 degrees C then at 20 degrees C, which gave us an explanation for the unusual slower rate of tracer efflux measured at 37 degrees C then that at 20 degrees C. The results obtained on BLM showed that the pore inactivation was due to a decrease in the number of pores but not to a change of their dwell time or conductance.

  13. Formation of "solvent-free" black lipid bilayer membranes from glyceryl monooleate dispersed in squalene.

    Science.gov (United States)

    White, S H

    1978-09-01

    A simple technique for forming "black" lipid bilayer membranes containing negligible amounts of alkyl solvent is described. The membranes are formed by the method of Mueller et al (Circulation. 1962. 26:1167.) from glyceryl monooleate (GMO) dispersed in squalene. The squalene forms an annulus to satisfy the boundary conditions of the planar bilayer but does not appear to dissolve noticeably in the bilayer itself. The specific geometric capacitance (Cg) of the membranes at 20 degrees C formed by this technique is 0.7771 +/- 0.0048 muF/cm2. Theoretical estimates of Cg for solvent-free bilayers range from 0.75 to 0.81 muF/cm2. Alkane-free GMO bilayers formed from n-octadecane by the solvent freeze-out method of White (Biochim. Biophys. Acta. 1974. 356:8) have values of Cg = 0.7903 +/- 0.0013 muF/cm2 at 20.5 degrees C. The agreement between the various values of Cg strongly suggests that the bilayers are free of squalene. DC potentials applied to the bilayers have no detectable effect on the value of Cg, as expected for solvent-free films. The ability to form bilayers essentially free of the solvent used in the forming solution makes it possible to determine the area per molecule of the surface active lipid in the bilayer. The area per molecule of GMO at 20 degrees C is estimated to be 37.9 +/- 0.2 A2.

  14. Breakdown of interlocking domains may contribute to formation of membranous globules and lens opacity in ephrin-A5(-/-) mice.

    Science.gov (United States)

    Biswas, Sondip; Son, Alexander; Yu, Qili; Zhou, Renping; Lo, Woo-Kuen

    2016-04-01

    Ephrin-A5, a ligand of the Eph family of receptor tyrosine kinases, plays a key role in lens fiber cell packing and cell-cell adhesion, with approximately 87% of ephrin-A5(-/-) mice develop nuclear cataracts. Here, we investigated the extensive formation of light-scattering globules associated with breakdown of interlocking protrusions during lens opacification in ephrin-A5(-/-) mice. Lenses from wild-type (WT) and ephrin-A5(-/-) mice between 2 and 21 weeks old were studied with light and electron microscopy, immunofluorescence labeling, freeze-fracture TEM and filipin cytochemistry for membrane cholesterol detection. Lens opacities with various densities were first observed in ephrin-A5(-/-) mice at around 60 days old. Dense cataracts in the mutant lenses were seen primarily in the nuclear region surrounded by transparent cortices from all eyes examined. We confirmed that a majority of nuclear cataracts were dislocated posteriorly and ruptured the thinner posterior lens capsule. SEM analysis indicated that numerous interlocking protrusions and wavy ridge-and-valley membrane surfaces in deep cortical and nuclear fibers did not cause lens opacity in both transparent ephrin-A5(-/-) and WT mice. In contrast, abundant isolated membranous globules of approximately 1000 nm in size were distributed randomly along the intact fiber cells during early stage of all ephrin-A5(-/-) cataracts examined. A further examination using both SEM and TEM revealed that isolated globules were generated from the disintegrated interlocking protrusions originally located along the corners of hexagonal fiber cells. Freeze-fracture TEM further revealed the association of square-array aquaporin junctions with both isolated globules and interlocking membrane domains. This study reports for the first time that disrupted interlocking protrusions are the source of numerous large membranous globules that contribute to light scattering and nuclear cataracts in the ephrin-A5(-/-) mice. Our results

  15. Detection of Membrane Fluidity in Submitochondrial Particles of Platelets and Erythrocyte Membranes from Mexican Patients with Alzheimer Disease by Intramolecular Excimer Formation of 1,3 Dipyrenylpropane

    Directory of Open Access Journals (Sweden)

    G.G. Ortiz

    2008-01-01

    Full Text Available It has been suggested that mitochondrial dysfunction and defects in membrane structure could be implied in AD pathogenesis. The aim of the present work was the study of membrane fluidity in submitochondrial platelet particles and erythrocyte membranes from Mexican patients. Blood samples were obtained from 30 patients with Alzheimer disease and 30 aged-matched control subjects. Membrane fluidity determinations were done using a very low concentration of the fluorescent dipyrenylpropane probe incorporated in both types of membranes. This probe is able to give excimer and monomer fluorescence, therefore it can be used to monitor fluidity changes in biological membranes.

  16. Vipp1 is required for basic thylakoid membrane formation but not for the assembly of thylakoid protein complexes.

    Science.gov (United States)

    Aseeva, Elena; Ossenbühl, Friederich; Sippel, Claudia; Cho, Won K; Stein, Bernhard; Eichacker, Lutz A; Meurer, Jörg; Wanner, Gerhard; Westhoff, Peter; Soll, Jürgen; Vothknecht, Ute C

    2007-02-01

    Vipp1 (vesicle inducing protein in plastids 1) is found in cyanobacteria and chloroplasts where it is essential for thylakoid formation. Arabidopsis thaliana mutant plants with a reduction of Vipp1 to about 20% of wild type content become albinotic at an early stage. We propose that this drastic phenotype results from an inability of the remaining Vipp1 protein to assemble into a homo-oligomeric complex, indicating that oligomerization is a prerequisite for Vipp1 function. A Vipp1-ProteinA fusion protein, expressed in the Deltavipp1 mutant background, is able to reinstate oligomerization and restore photoautotrophic growth. Plants containing Vipp1-ProteinA in amounts comparable to Vipp1 in the wild type exhibit a wild type phenotype. However, plants with a reduced amount of Vipp1-ProteinA protein are growth-retarded and significantly paler than the wild type. This phenotype is caused by a decrease in thylakoid membrane content and a concomitant reduction in photosynthetic activity. To the extent that thylakoid membranes are made in these plants they are properly assembled with protein-pigment complexes and are photosynthetically active. This strongly supports a function of Vipp1 in basic thylakoid membrane formation and not in the functional assembly of thylakoid protein complexes. Intriguingly, electron microscopic analysis shows that chloroplasts in the mutant plants are not equally affected by the Vipp1 shortage. Indeed, a wide range of different stages of thylakoid development ranging from wild-type-like chloroplasts to plastids nearly devoid of thylakoids can be observed in organelles of one and the same cell.

  17. Membrane-Mediated Decrease in Root Exudation Responsible for Phorphorus Inhibition of Vesicular-Arbuscular Mycorrhiza Formation

    Science.gov (United States)

    Graham, James H.; Leonard, Robert T.; Menge, John A.

    1981-01-01

    The mechanism responsible for phosphorus inhibition of vesicular-arbuscular mycorrhiza formation in sudangrass (Sorghum vulgare Pers.) was investigated in a phosphorus-deficient sandy soil (0.5 micrograms phosphorus per gram soil) amended with increasing levels of phosphorus as superphosphate (0, 28, 56, 228 micrograms per gram soil). The root phosphorus content of 4-week-old plants was correlated with the amount of phosphorus added to the soil. Root exudation of amino acids and reducing sugars was greater for plants grown in phosphorus-deficient soil than for those grown in the phosphorus-treated soils. The increase in exudation corresponded with changes in membrane permeability of phosphorus-deficient roots, as measured by K+ (86Rb) efflux, rather than with changes in root content of reducing sugars and amino acids. The roots of phosphorus-deficient plants inoculated at 4 weeks with Glomus fasciculatus were 88% infected after 9 weeks as compared to less than 25% infection in phosphorus-sufficient roots; these differences were correlated with root exudation at the time of inoculation. For plants grown in phosphorus-deficient soil, infection by vesicular-arbuscular mycorrhizae increased root phosphorus which resulted in a decrease in root membrane permeability and exudation compared to nonmycorrhizal plants. It is proposed that, under low phosphorus nutrition, increased root membrane permeability leads to net loss of metabolites at sufficient levels to sustain the germination and growth of the mycorrhizal fungus during pre- and postinfection. Subsequently, mycorrhizal infection leads to improvement of root phosphorus nutrition and a reduction in membrane-mediated loss of root metabolites. PMID:16661955

  18. Vancomycin-induced biofilm formation by methicillin-resistant Staphylococcus aureus is associated with the secretion of membrane vesicles.

    Science.gov (United States)

    He, Xinlong; Yuan, Fenglai; Lu, Feng; Yin, Yinyan; Cao, Jun

    2017-09-01

    Chronic burn wound infections caused by Stapyhylococcus aureus (S. aureus) are largely associated with biofilm formation. However, the mechanism by which S. aureus form biofilm in clinical environments is far less understood. In the present study we addressed the association between biofilm formation and membrane vesicle (MV) secretion of S. aureus during vancomycin treatment. A representative methicillin-resistant S. aureus (MRSA) strain BWMR22 obtained from a chronic burn wound was used in this study. Transmission electron microscope was used to observe the MV secretion. Fourier transform infrared spectroscopy was used to analyze the chemical component of MV. Biofilm formation was assayed under conditions of sub-inhibitory concentrations of vancomycin. Functional potencies of MV in surface adhesion and auto-aggregation were assayed in the presence of additional purified MVs. Biofilm formation by S. aureus BWMR22 was enhanced in the presence of sub-inhibitory concentration of vancomycin. Vancomycin treatment caused an increase in the chemical composition of protein relative to carbohydrates of secreted MVs, a property which was highly associated with bacterial hydrophobicity, surface adhesion, and intercellular aggregation. These findings suggest that MV secretion is correlated with biofilm formation by MRSA especially under clinical conditions with improper vancomycin chemotherapy. This study first demonstrates a potential role of MVs in the biofilm formation by S. aureus, stresses on the importance of avoiding low dose of antibiotic therapy in controlling of S. aureus infections, and provides further information to reveal the mechanisms behind MRSA infections. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Cell killing by simian virus 40: impairment of membrane formation and function.

    Science.gov (United States)

    Norkin, L C

    1977-03-01

    Simian virus 40 infection of the CV-1 line of green monkey kidney cells results in the release of mitochondrial malic dehydrogenase as early as 24 h. Released malic dehydrogenase is detected in the cytoplasm prior to its appearance in the overlay medium. Infected cells lose the ability to consume oxygen between 48 and 56 h, and damage to the elctron transport system is indicated. Nevertheless, cellular ATP levels remain high as late as 72 h. Infection leads to a stimulation of membrane phospholipid synthesis, which reaches a peak at about 32 h. This is followed by a severe decline in new membrane synthesis, which correlates in time with the release of cytoplasmic lactic dehydrogenase into the overlay media. Lactic dehydrogenase release precedes the accumulation of trypan blue-stainable cells by about 6 h. Infection had no effect on the turnover of prelabeled membrane phospholipids. An early simian virus 40 mutant, tsA58, and a late mutant, tsB11, are both less effective than wild-type virus at causing reduced levels of phospholipid synthesis, enzyme release, and the accumulation of trypan blue-stainable cells. Another late mutant, tsB8, is similar to wild-type virus in these respects. At 64 h, there is no detectable cell-associated lactic dehydrogenase and nearly all the cells are trypan blue stainable. Nevertheless, at concentrations of deoxyglucose in the medium below the transport Km, deoxyglucose uptake was similar in infected and control cultures. With higher concentrations of deoxyglucose in the medium, uptake by the infected cultures exceeded that by the control cultures.

  20. Mutations in Lama1 disrupt retinal vascular development and inner limiting membrane formation.

    Science.gov (United States)

    Edwards, Malia M; Mammadova-Bach, Elmina; Alpy, Fabien; Klein, Annick; Hicks, Wanda L; Roux, Michel; Simon-Assmann, Patricia; Smith, Richard S; Orend, Gertraud; Wu, Jiang; Peachey, Neal S; Naggert, Jürgen K; Lefebvre, Olivier; Nishina, Patsy M

    2010-03-05

    The Neuromutagenesis Facility at the Jackson Laboratory generated a mouse model of retinal vasculopathy, nmf223, which is characterized clinically by vitreal fibroplasia and vessel tortuosity. nmf223 homozygotes also have reduced electroretinogram responses, which are coupled histologically with a thinning of the inner nuclear layer. The nmf223 locus was mapped to chromosome 17, and a missense mutation was identified in Lama1 that leads to the substitution of cysteine for a tyrosine at amino acid 265 of laminin alpha1, a basement membrane protein. Despite normal localization of laminin alpha1 and other components of the inner limiting membrane, a reduced integrity of this structure was suggested by ectopic cells and blood vessels within the vitreous. Immunohistochemical characterization of nmf223 homozygous retinas demonstrated the abnormal migration of retinal astrocytes into the vitreous along with the persistence of hyaloid vasculature. The Y265C mutation significantly reduced laminin N-terminal domain (LN) interactions in a bacterial two-hybrid system. Therefore, this mutation could affect interactions between laminin alpha1 and other laminin chains. To expand upon these findings, a Lama1 null mutant, Lama1(tm1.1Olf), was generated that exhibits a similar but more severe retinal phenotype than that seen in nmf223 homozygotes. The increased severity of the Lama1 null mutant phenotype is probably due to the complete loss of the inner limiting membrane in these mice. This first report of viable Lama1 mouse mutants emphasizes the importance of this gene in retinal development. The data presented herein suggest that hypomorphic mutations in human LAMA1 could lead to retinal disease.

  1. Formation of complement membrane attack complex in mammalian cerebral cortex evokes seizures and neurodegeneration.

    Science.gov (United States)

    Xiong, Zhi-Qi; Qian, Weihua; Suzuki, Katsuaki; McNamara, James O

    2003-02-01

    The complement system consists of >30 proteins that interact in a carefully regulated manner to destroy invading bacteria and prevent the deposition of immune complexes in normal tissue. This complex system can be activated by diverse mechanisms proceeding through distinct pathways, yet all converge on a final common pathway in which five proteins assemble into a multimolecular complex, the membrane attack complex (MAC). The MAC inserts into cell membranes to form a functional pore, resulting in ion flux and ultimately osmotic lysis. Immunohistochemical evidence of the MAC decorating neurons in cortical gray matter has been identified in multiple CNS diseases, yet the deleterious consequences, if any, of MAC deposition in the cortex of mammalian brain in vivo are unknown. Here we demonstrate that the sequential infusion of individual proteins of the membrane attack pathway (C5b6, C7, C8, and C9) into the hippocampus of awake, freely moving rats induced both behavioral and electrographic seizures as well as cytotoxicity. The onset of seizures occurred during or shortly after the infusion of C8/C9. Neither seizures nor cytotoxicity resulted from the simultaneous infusion of all five proteins premixed in vitro. The requirement for the sequential infusion of all five proteins together with the temporal relationship of seizure onset to infusions of C8/C9 implies that the MAC was formed in vivo and triggered both seizures and cytotoxicity. Deposition of the complement MAC in cortical gray matter may contribute to epileptic seizures and cell death in diverse diseases of the human brain.

  2. Requirements for the formation of membrane pores by the reovirus myristoylated micro1N peptide.

    Science.gov (United States)

    Zhang, Lan; Agosto, Melina A; Ivanovic, Tijana; King, David S; Nibert, Max L; Harrison, Stephen C

    2009-07-01

    The outer capsid of the nonenveloped mammalian reovirus contains 200 trimers of the micro1 protein, each complexed with three copies of the protector protein sigma3. Conformational changes in micro1 following the proteolytic removal of sigma3 lead to release of the myristoylated N-terminal cleavage fragment micro1N and ultimately to membrane penetration. The micro1N fragment forms pores in red blood cell (RBC) membranes. In this report, we describe the interaction of recombinant micro1 trimers and synthetic micro1N peptides with both RBCs and liposomes. The micro1 trimer mediates hemolysis and liposome disruption under conditions that promote the micro1 conformational change, and mutations that inhibit micro1 conformational change in the context of intact virus particles also prevent liposome disruption by particle-free micro1 trimer. Autolytic cleavage to form micro1N is required for hemolysis but not for liposome disruption. Pretreatment of RBCs with proteases rescues hemolysis activity, suggesting that micro1N cleavage is not required when steric barriers are removed. Synthetic myristoylated micro1N peptide forms size-selective pores in liposomes, as measured by fluorescence dequenching of labeled dextrans of different sizes. Addition of a C-terminal solubility tag to the peptide does not affect activity, but sequence substitution V13N or L36D reduces liposome disruption. These substitutions are in regions of alternating hydrophobic residues. Their locations, the presence of an N-terminal myristoyl group, and the full activity of a C-terminally extended peptide, along with circular dichroism data that indicate prevalence of beta-strand secondary structure, suggest a model in which micro1N beta-hairpins assemble in the membrane to form a beta-barrel pore.

  3. Pattern formation in biological fluids II: cell deformation in shear fields evidences convective membrane organisation

    CERN Document Server

    Lofthouse, J

    2004-01-01

    The mechanical behaviour and symmetry-breaking shape deformation of red blood cells subjected to shear flows is used to demonstrate that far from being random fluids, both the membrane and cytoplasm of every biological cell undergo spatially organised convective and shear driven flows when the cell maintains a Near Equilibrium state through continuousmetabolic activity. The model demonstrates that fluid bifurcation events drive cell shape changes, rather than a Meccano like cytoskeletal structure, and represents a significant Gestalt shift in models of cell mechanics.

  4. Recombinant Bone Morphogenetic Protein 2 Stimulates the Remodeling Chitosan-Based Porous Scaffold Into Hyaline-like Cartilage: Study in Heterotopic Implantation

    Directory of Open Access Journals (Sweden)

    Nurshat M. Gaifullin

    2013-09-01

    Full Text Available To study the morphology of remodeling the chitosan-based three-dimensional porous scaffold, containing bone morphogenetic protein-2 (BMP-2 for chondroinduction, the experiments with heterotopic implantation using 28 Wistar rats were carried out. Scaffolds with growth factor (n=12 or without it (n=12, against intact control (n=4 were implanted subcutaneously. Classical methods of histology and morphometry as well as immune histochemical markers (CD-68, CD-31, MMP-9, TIMP-1, and osteonectin expression, one used to investigate zone of remodeling in euthanized animals at 4 and 8 weeks after implantation. The BMP-2 application provides more intensive and rapid new cartilage formation from the scaffold matter. The additional chondroinductive effect proved more intensive settlement and proliferation of chondral cells in the regenerate, expression of chondral phenotype with the building the hyaline-like matrix, and the supporting necessary balance between the matrix metalloproteinases and their tissue inhibitors.

  5. Characterization of Natural Organic Matter and Disinfection Byproducts Formation Potential in Pilot-Scale Coagulation-Ultrafiltration Membrane Combined Process in Winter

    Institute of Scientific and Technical Information of China (English)

    张耀宗; 王启山; 何凤华; 丁莎莎

    2010-01-01

    A pilot-scale ultrafiltration membrane plant was set up for treating Luanhe River water with flocculating and precipitation process of waterworks.The aim is to investigate the variation and characteristics of natural organic matter and disinfection byproducts formation potential in the whole process in winter.The results show that dissolved organic matter(DOM),UV254,trihalomethanes formation potential(THMsFP) and haloacetic acids formation potential(HAAsFP) of Luanhe River water were mainly distributed in t...

  6. Formation of chelating agent driven anodized TiO2 nanotubular membrane and its photovoltaic application

    Science.gov (United States)

    Banerjee, Subarna; Misra, Mano; Mohapatra, Susanta K.; Howard, Cameron; Mohapatra, Srikanta K.; Kamilla, Sushanta K.

    2010-04-01

    Titania (TiO2) nanotubular arrays provide an exciting material for dye sensitizing solar cells (DSSC) because of their large surface area, lower recombination losses, and fast charge transport properties along the nanotubes. In this paper, design of a next generation DSSC using a TiO2 nanotubular membrane is discussed. A single step, green process is developed to produce stable large area, free-standing TiO2 nanotubular films (in a short time, 30-60 min) by anodizing Ti using an organic electrolyte, containing disodium salt of ethylene diaminetetraacetic acid (Na2[H2EDTA]) as complexing agent, and subsequent drying. Transparent, crack-free TiO2 films, 20-41 µm thick containing ordered hexagonal TiO2 nanotubes are achieved by this process. Films having a geometrical area up to 16.5 cm2 with pore openings of 182 nm have been obtained. These films have been etched to form membranes which provide an exciting prospect for front side illuminated DSSC with good mass and photon transport properties as well as wettability. A photovoltaic efficiency of 2.7% is achieved using a front side illuminated DSSC compared to 1.77% using back side illumination.

  7. Formation of chelating agent driven anodized TiO(2) nanotubular membrane and its photovoltaic application.

    Science.gov (United States)

    Banerjee, Subarna; Misra, Mano; Mohapatra, Susanta K; Howard, Cameron; Mohapatra, Srikanta K; Kamilla, Sushanta K

    2010-04-09

    Titania (TiO(2)) nanotubular arrays provide an exciting material for dye sensitizing solar cells (DSSC) because of their large surface area, lower recombination losses, and fast charge transport properties along the nanotubes. In this paper, design of a next generation DSSC using a TiO(2) nanotubular membrane is discussed. A single step, green process is developed to produce stable large area, free-standing TiO(2) nanotubular films (in a short time, 30-60 min) by anodizing Ti using an organic electrolyte, containing disodium salt of ethylene diaminetetraacetic acid (Na(2)[H(2)EDTA]) as complexing agent, and subsequent drying. Transparent, crack-free TiO(2) films, 20-41 microm thick containing ordered hexagonal TiO(2) nanotubes are achieved by this process. Films having a geometrical area up to 16.5 cm(2) with pore openings of 182 nm have been obtained. These films have been etched to form membranes which provide an exciting prospect for front side illuminated DSSC with good mass and photon transport properties as well as wettability. A photovoltaic efficiency of 2.7% is achieved using a front side illuminated DSSC compared to 1.77% using back side illumination.

  8. Modulation of Wound Healing and Scar Formation by MG53 Protein-mediated Cell Membrane Repair*

    Science.gov (United States)

    Li, Haichang; Duann, Pu; Lin, Pei-Hui; Zhao, Li; Fan, Zhaobo; Tan, Tao; Zhou, Xinyu; Sun, Mingzhai; Fu, Minghuan; Orange, Matthew; Sermersheim, Matthew; Ma, Hanley; He, Duofen; Steinberg, Steven M.; Higgins, Robert; Zhu, Hua; John, Elizabeth; Zeng, Chunyu; Guan, Jianjun; Ma, Jianjie

    2015-01-01

    Cell membrane repair is an important aspect of physiology, and disruption of this process can result in pathophysiology in a number of different tissues, including wound healing, chronic ulcer and scarring. We have previously identified a novel tripartite motif family protein, MG53, as an essential component of the cell membrane repair machinery. Here we report the functional role of MG53 in the modulation of wound healing and scarring. Although MG53 is absent from keratinocytes and fibroblasts, remarkable defects in skin architecture and collagen overproduction are observed in mg53−/− mice, and these animals display delayed wound healing and abnormal scarring. Recombinant human MG53 (rhMG53) protein, encapsulated in a hydrogel formulation, facilitates wound healing and prevents scarring in rodent models of dermal injuries. An in vitro study shows that rhMG53 protects against acute injury to keratinocytes and facilitates the migration of fibroblasts in response to scratch wounding. During fibrotic remodeling, rhMG53 interferes with TGF-β-dependent activation of myofibroblast differentiation. The resulting down-regulation of α smooth muscle actin and extracellular matrix proteins contributes to reduced scarring. Overall, these studies establish a trifunctional role for MG53 as a facilitator of rapid injury repair, a mediator of cell migration, and a modulator of myofibroblast differentiation during wound healing. Targeting the functional interaction between MG53 and TGF-β signaling may present a potentially effective means for promoting scarless wound healing. PMID:26306047

  9. Pore formation by antimicrobial peptides: structural tendencies in bulk and quasi-2D membrane systems

    Science.gov (United States)

    Gordon, Vernita; Yang, Lihua; Davis, Matthew; Som, A.; Tew, G.; Wong, Gerard

    2007-03-01

    Antimicrobial peptides are cationic, amphiphilic structures that are key components of innate immunity. A prototypical family of synthetic analogs are the phenylene ethynylene antimicrobial oligomers (AMOs), which have hydrophobic alkyl chains connected to cationic hydrophilic regions. Synchrotron small-angle x-ray scattering (SAXS) shows that when AMO is mixed with concentrated model membranes, initially in the form of Small Unilamellar Vesicles, the sample forms the inverted hexagonal phase. This is a 3-dimensional phase characterized by a regular array of size-defined water channels. We demonstrate how this structural tendency is expressed when AMOs interact with dilute model membranes in the form of Giant Unilamellar Vesicles (GUVs). Using confocal microscopy, we see that applying AMO to the GUVs causes small encapsulated molecules to be released while large molecules are retained, indicating that size-defined pores have been created. Examining the partial release of polydisperse intermediately-sized molecules allows a closer measurement of the pore size, and there are indications that this single-vesicle microscopy will allow elucidation of the kinetics of the pore-forming process.

  10. Developments in dynamic MR elastography for in vitro biomechanical assessment of hyaline cartilage under high-frequency cyclical shear.

    Science.gov (United States)

    Lopez, Orlando; Amrami, Kimberly K; Manduca, Armando; Rossman, Phillip J; Ehman, Richard L

    2007-02-01

    The design, construction, and evaluation of a customized dynamic magnetic resonance elastography (MRE) technique for biomechanical assessment of hyaline cartilage in vitro are described. For quantification of the dynamic shear properties of hyaline cartilage by dynamic MRE, mechanical excitation and motion sensitization were performed at frequencies in the kilohertz range. A custom electromechanical actuator and a z-axis gradient coil were used to generate and image shear waves throughout cartilage at 1000-10,000 Hz. A radiofrequency (RF) coil was also constructed for high-resolution imaging. The technique was validated at 4000 and 6000 Hz by quantifying differences in shear stiffness between soft ( approximately 200 kPa) and stiff ( approximately 300 kPa) layers of 5-mm-thick bilayered phantoms. The technique was then used to quantify the dynamic shear properties of bovine and shark hyaline cartilage samples at frequencies up to 9000 Hz. The results demonstrate that one can obtain high-resolution shear stiffness measurements of hyaline cartilage and small, stiff, multilayered phantoms at high frequencies by generating robust mechanical excitations and using large magnetic field gradients. Dynamic MRE can potentially be used to directly quantify the dynamic shear properties of hyaline and articular cartilage, as well as other cartilaginous materials and engineered constructs. (c) 2007 Wiley-Liss, Inc.

  11. A comparison of different bioinks for 3D bioprinting of fibrocartilage and hyaline cartilage.

    Science.gov (United States)

    Daly, Andrew C; Critchley, Susan E; Rencsok, Emily M; Kelly, Daniel J

    2016-10-07

    Cartilage is a dense connective tissue with limited self-repair capabilities. Mesenchymal stem cell (MSC) laden hydrogels are commonly used for fibrocartilage and articular cartilage tissue engineering, however they typically lack the mechanical integrity for implantation into high load bearing environments. This has led to increased interested in 3D bioprinting of cell laden hydrogel bioinks reinforced with stiffer polymer fibres. The objective of this study was to compare a range of commonly used hydrogel bioinks (agarose, alginate, GelMA and BioINK™) for their printing properties and capacity to support the development of either hyaline cartilage or fibrocartilage in vitro. Each hydrogel was seeded with MSCs, cultured for 28 days in the presence of TGF-β3 and then analysed for markers indicative of differentiation towards either a fibrocartilaginous or hyaline cartilage-like phenotype. Alginate and agarose hydrogels best supported the development of hyaline-like cartilage, as evident by the development of a tissue staining predominantly for type II collagen. In contrast, GelMA and BioINK(™) (a PEGMA based hydrogel) supported the development of a more fibrocartilage-like tissue, as evident by the development of a tissue containing both type I and type II collagen. GelMA demonstrated superior printability, generating structures with greater fidelity, followed by the alginate and agarose bioinks. High levels of MSC viability were observed in all bioinks post-printing (∼80%). Finally we demonstrate that it is possible to engineer mechanically reinforced hydrogels with high cell viability by co-depositing a hydrogel bioink with polycaprolactone filaments, generating composites with bulk compressive moduli comparable to articular cartilage. This study demonstrates the importance of the choice of bioink when bioprinting different cartilaginous tissues for musculoskeletal applications.

  12. Diversification of the AlpB Outer Membrane Protein of Helicobacter pylori Affects Biofilm Formation and Cellular Adhesion.

    Science.gov (United States)

    Yonezawa, Hideo; Osaki, Takako; Fukutomi, Toshiyuki; Hanawa, Tomoko; Kurata, Satoshi; Zaman, Cynthia; Hojo, Fuhito; Kamiya, Shigeru

    2017-03-15

    Helicobacter pylori is one of the most common causes of bacterial infection in humans, and it forms biofilms on human gastric mucosal epithelium as well as on in vitro abiotic surfaces. Bacterial biofilm is critical not only for environmental survival but also for successful infection. We previously demonstrated that strain TK1402, which was isolated from a Japanese patient with duodenal and gastric ulcers, has high biofilm-forming ability in vitro relative to other strains. In addition, we showed that outer membrane vesicles (OMV) play an important role in biofilm formation. The aim of this study was to analyze which protein(s) in the OMV contributes to biofilm formation in TK1402. We obtained a spontaneous mutant strain derived from TK1402 lacking biofilm-forming ability. The protein profiles of the OMV were compared between this mutant strain and the wild type, and it was found that AlpB, an outer membrane protein in the OMV of the mutant strain, was markedly decreased compared to that of the wild type. Restoration of TK1402 alpB to the mutant strain fully recovered the ability to form biofilm. However, restoration with alpB from other strains demonstrated incomplete recovery of biofilm-forming ability. We therefore inferred that the variable region of AlpB (amino acid positions 121 to 146) was involved in TK1402 biofilm formation. In addition, diversification of the AlpB sequence was shown to affect the ability to adhere to AGS cells. These results demonstrate a new insight into the molecular mechanisms of host colonization by H. pyloriIMPORTANCE Bacterial biofilm is critical not only for environmental survival but also for successful infection. The mechanism of Helicobacter pylori adherence to host cells mediated by cell surface adhesins has been the focus of many studies, but little is known regarding factors involved in H. pylori biofilm formation. Our study demonstrated that AlpB plays an important role in biofilm formation and that this property depends

  13. Nano composite membrane-electrode assembly formation for fuel cell-modeling aspects

    Science.gov (United States)

    Vaivars, G.; Linkov, V.

    2007-12-01

    Long term stability is an essential requirement for fuel cell applications in automobile and stationary energy systems. In these systems the agglomeration of the catalyst nanoparticles is a well-known phenomenon which cannot be easily overcome or compensated for by re-designing the system. A direct result of this occurrence is the irreversible decrease of the electrochemical performance. Irregularities in electric field distribution are one root cause for migration and subsequent agglomeration of the catalyst nanoparticle. In this work, the impact of the electrode mechanical deformation on electric field distribution was studied using a computer modeling approach. Model of a Proton Exchange Membrane (PEM) fuel cell with interdigitated flow field from Comsol Chemical Engineering/Electrochemical Engineering Module library was used for simulations. It was established that by minimizing the backing layer deformation it is possible to achieve some improvement in current distribution.

  14. Variation of the input resistance and membrane potential of a neuron in trace formation.

    Science.gov (United States)

    D'yakonova, T L; Mikhal'tsev, I E

    1985-01-01

    Trace changes in electrical activity, input resistance (Rinp), and membrane potential (MP) of brain neurons are studied in the mollusk Limnaea stagnalis for intracellular stimulation with a sinusoidal threshold current with a frequency of 0.1 Hz during 20 min. Some neurons are shown to exhibit an effect of facilitation, a rise in the level of activity being attending by an increase in Rinp and depolarization. Other neurons displayed lowered activity with a decrease of Rinp and hyperpolarization. The selectivity of the Rinp variations relative to the parameters of the stimuli (maximum changes at the frequency of the current used) suggests that it is precisely trace changes of Rinp which lie at the basis of the neuronal plasticity in "learning." Some neurons in this series of experiments did not alter their electrical response, Rinp, or MP for stimulation. The possible reason for the non-uniform reaction of different neurons to identical stimulation is discussed.

  15. Nano composite membrane-electrode assembly formation for fuel cell-modeling aspects

    Energy Technology Data Exchange (ETDEWEB)

    Vaivars, G [Institute of Solid State Physics of University of Latvia, Riga (Latvia); Linkov, V [University of the Western Cape, South African Institute of Advanced Material Chemistry, Cape Town, Western Cape (South Africa)

    2007-12-15

    Long term stability is an essential requirement for fuel cell applications in automobile and stationary energy systems. In these systems the agglomeration of the catalyst nanoparticles is a well-known phenomenon which cannot be easily overcome or compensated for by re-designing the system. A direct result of this occurrence is the irreversible decrease of the electrochemical performance. Irregularities in electric field distribution are one root cause for migration and subsequent agglomeration of the catalyst nanoparticle. In this work, the impact of the electrode mechanical deformation on electric field distribution was studied using a computer modeling approach. Model of a Proton Exchange Membrane (PEM) fuel cell with interdigitated flow field from Comsol Chemical Engineering/Electrochemical Engineering Module library was used for simulations. It was established that by minimizing the backing layer deformation it is possible to achieve some improvement in current distribution.

  16. Diffusion mediated coagulation and fragmentation based study of domain formation in lipid bilayer membrane

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Laxminarsimha V., E-mail: laxman@iitk.ac.in [Mechanics and Applied Mathematics Group, Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016 (India); Roy, Subhradeep [Department of Biomedical Engineering and Mechanics (MC 0219), Virginia Tech, 495 Old Turner Street, Blacksburg, VA 24061 (United States); Das, Sovan Lal [Mechanics and Applied Mathematics Group, Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016 (India)

    2017-01-15

    We estimate the equilibrium size distribution of cholesterol rich micro-domains on a lipid bilayer by solving Smoluchowski equation for coagulation and fragmentation. Towards this aim, we first derive the coagulation kernels based on the diffusion behaviour of domains moving in a two dimensional membrane sheet, as this represents the reality better. We incorporate three different diffusion scenarios of domain diffusion into our coagulation kernel. Subsequently, we investigate the influence of the parameters in our model on the coagulation and fragmentation behaviour. The observed behaviours of the coagulation and fragmentation kernels are also manifested in the equilibrium domain size distribution and its first moment. Finally, considering the liquid domains diffusing in a supported lipid bilayer, we fit the equilibrium domain size distribution to a benchmark solution.

  17. Modulation of wound healing and scar formation by MG53 protein-mediated cell membrane repair.

    Science.gov (United States)

    Li, Haichang; Duann, Pu; Lin, Pei-Hui; Zhao, Li; Fan, Zhaobo; Tan, Tao; Zhou, Xinyu; Sun, Mingzhai; Fu, Minghuan; Orange, Matthew; Sermersheim, Matthew; Ma, Hanley; He, Duofen; Steinberg, Steven M; Higgins, Robert; Zhu, Hua; John, Elizabeth; Zeng, Chunyu; Guan, Jianjun; Ma, Jianjie

    2015-10-02

    Cell membrane repair is an important aspect of physiology, and disruption of this process can result in pathophysiology in a number of different tissues, including wound healing, chronic ulcer and scarring. We have previously identified a novel tripartite motif family protein, MG53, as an essential component of the cell membrane repair machinery. Here we report the functional role of MG53 in the modulation of wound healing and scarring. Although MG53 is absent from keratinocytes and fibroblasts, remarkable defects in skin architecture and collagen overproduction are observed in mg53(-/-) mice, and these animals display delayed wound healing and abnormal scarring. Recombinant human MG53 (rhMG53) protein, encapsulated in a hydrogel formulation, facilitates wound healing and prevents scarring in rodent models of dermal injuries. An in vitro study shows that rhMG53 protects against acute injury to keratinocytes and facilitates the migration of fibroblasts in response to scratch wounding. During fibrotic remodeling, rhMG53 interferes with TGF-β-dependent activation of myofibroblast differentiation. The resulting down-regulation of α smooth muscle actin and extracellular matrix proteins contributes to reduced scarring. Overall, these studies establish a trifunctional role for MG53 as a facilitator of rapid injury repair, a mediator of cell migration, and a modulator of myofibroblast differentiation during wound healing. Targeting the functional interaction between MG53 and TGF-β signaling may present a potentially effective means for promoting scarless wound healing. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  18. Poly(2,6-dimethyl-1,4-phenylene oxide) Blended with Poly (vinylbenzyl chloride)-b-polystyrene for the Formation of Anion Exchange Membranes

    Science.gov (United States)

    2014-08-14

    documentation. 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS (ES) U.S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 Anion ...functionalization reached high conversion as characterized by ion exchange capacity (IEC) measurements. The PPO blend anion exchange membranes (AEMs...vinylbenzyl chloride)‑b‑polystyrene for the Formation of Anion Exchange Membranes Yifan Li,† Aaron C. Jackson,‡ Frederick L. Beyer,‡ and Daniel M

  19. Microfluidic Formation of Membrane-Free Aqueous Coacervate Droplets in Water.

    Science.gov (United States)

    van Swaay, Dirk; Tang, T-Y Dora; Mann, Stephen; de Mello, Andrew

    2015-07-13

    We report on the formation of coacervate droplets from poly(diallyldimethylammonium chloride) with either adenosine triphosphate or carboxymethyl-dextran using a microfluidic flow-focusing system. The formed droplets exhibit improved stability and narrower size distributions for both coacervate compositions when compared to the conventional vortex dispersion techniques. We also demonstrate the use of two parallel flow-focusing channels for the simultaneous formation and co-location of two distinct populations of coacervate droplets containing different DNA oligonucleotides, and that the populations can coexist in close proximity up to 48 h without detectable exchange of genetic information. Our results show that the observed improvements in droplet stability and size distribution may be scaled with ease. In addition, the ability to encapsulate different materials into coacervate droplets using a microfluidic channel structure allows for their use as cell-mimicking compartments.

  20. The Presence of Sterols Favors Sticholysin I-Membrane Association and Pore Formation Regardless of Their Ability to Form Laterally Segregated Domains.

    Science.gov (United States)

    Pedrera, Lohans; Gomide, Andreza B; Sánchez, Rafael E; Ros, Uris; Wilke, Natalia; Pazos, Fabiola; Lanio, María E; Itri, Rosangela; Fanani, María Laura; Alvarez, Carlos

    2015-09-15

    Sticholysin I (St I) is a pore-forming toxin (PFT) produced by the Caribbean Sea anemone Stichodactyla helianthus belonging to the actinoporin protein family, a unique class of eukaryotic PFT. As for actinoporins, it has been proposed that the presence of cholesterol (Chol) and the coexistence of lipid phases increase binding to the target membrane and pore-forming ability. However, little is known about the role of membrane structure and dynamics (phase state, fluidity, and the presence of lipid domains) on the activity of actinoporins or which regions of the membrane are the most favorable for protein insertion, oligomerization, and eventually pore formation. To gain insight into the role of membrane properties on the functional activity of St I, we studied its binding to monolayers and vesicles of phosphatidylcholine (PC), sphingomyelin (SM), and sterols inducing (ergosterol -Erg and cholesterol -Chol) or not (cholestenone - Cln) membrane phase segregation in liquid ordered (Lo) and liquid disordered (Ld) domains. This study revealed that St I binds and permeabilizes with higher efficiency sterol-containing membranes independently of their ability to form domains. We discuss the results in terms of the relevance of different membrane properties for the actinoporins mechanism of action, namely, molecular heterogeneity, specially potentiated in membranes with sterols inducers of phase separation (Chol or Erg) or Cln, a sterol noninducer of phase separation but with a high propensity to induce nonlamellar phase. The role of the Ld phase is pointed out as the most suitable platform for pore formation. In this regard, such regions in Chol-containing membranes seem to be the most favored due to its increased fluidity; this property promotes toxin insertion, diffusion, and oligomerization leading to pore formation.

  1. Formation of substrate-supported membranes from mixtures of long- and short-chain phospholipids.

    Science.gov (United States)

    Morigaki, Kenichi; Kimura, Shigeki; Okada, Keisuke; Kawasaki, Takashi; Kawasaki, Kazunori

    2012-06-26

    We studied the formation of substrate-supported planar phospholipid bilayers (SPBs) on glass and silica from mixtures of long- and short-chain phospholipids to assess the effects of detergent additives on SPB formation. 1,2-Hexyanoyl-sn-glycero-3-phosphocholine (DHPC-C6) and 1,2-heptanoyl-sn-glycero-3-phosphocholine (DHPC-C7) were chosen as short-chain phospholipids. 1-Palmitoyl-2-oleol-sn-glycero-3-phosphocholine (POPC) was used as a model long-chain phospholipid. Kinetic studies by quartz crystal microbalance with dissipation monitoring (QCM-D) showed that the presence of short-chain phospholipids significantly accelerated the formation of SPBs. Rapid rinsing with a buffer solution did not change the adsorbed mass on the surface if POPC/DHPC-C6 mixtures were used below the critical micelle concentration (cmc) of DHPC-C6, indicating that an SPB composed of POPC molecules remained on the surface. Fluorescence microscopy observation showed homogeneous SPBs, and the fluorescence recovery after photobleaching (FRAP) measurements gave a diffusion coefficient comparable to that for SPBs formed from POPC vesicles. However, mixtures of POPC/DHPC-C7 resulted in a smaller mass of lipid adsorption on the substrate. FRAP measurements also yielded significantly smaller diffusion coefficients, suggesting the presence of defects. The different behaviors for DHPC-C6 and DHPC-C7 point to the dual roles of detergents to enhance the formation of SPBs and to destabilize them, depending on their structures and aggregation properties.

  2. Role of Tractional Forces and Internal Limiting Membrane in Macular Hole Formation: Insights from Intraoperative Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    Elad Moisseiev

    2016-07-01

    Full Text Available We report the case of a 69-year-old patient who underwent vitrectomy for vitreomacular traction (VMT and developed a postoperative macular hole that was observed 1 week after surgery. The hole did not close by in-office fluid-gas exchange alone, but was achieved after repeat surgery with internal limiting membrane (ILM peeling. Intraoperative OCT (iOCT images from the first surgery revealed an occult macular hole that formed after VMT release. We discuss how iOCT findings provide insight into the role of the ILM in macular hole formation and emphasize the importance of carefully inspecting iOCT images in real time to avoid missing small but important findings.

  3. SMU.746-SMU.747, a putative membrane permease complex, is involved in aciduricity, acidogenesis, and biofilm formation in Streptococcus mutans.

    Science.gov (United States)

    Król, Jaroslaw E; Biswas, Saswati; King, Clay; Biswas, Indranil

    2014-01-01

    Dental caries induced by Streptococcus mutans is one of the most prevalent chronic infectious diseases worldwide. The pathogenicity of S. mutans relies on the bacterium's ability to colonize tooth surfaces and survive a strongly acidic environment. We performed an ISS1 transposon mutagenesis to screen for acid-sensitive mutants of S. mutans and identified an SMU.746-SMU.747 gene cluster that is needed for aciduricity. SMU.746 and SMU.747 appear to be organized in an operon and encode a putative membrane-associated permease. SMU.746- and SMU.747-deficient mutants showed a reduced ability to grow in acidified medium. However, the short-term or long-term acid survival capacity and F1F0 ATPase activity remained unaffected in the mutants. Furthermore, deletion of both genes did not change cell membrane permeability and the oxidative and heat stress responses. Growth was severely affected even with slight acidification of the defined medium (pH 6.5). The ability of the mutant strain to acidify the defined medium during growth in the presence of glucose and sucrose was significantly reduced, although the glycolysis rate was only slightly affected. Surprisingly, deletion of the SMU.746-SMU.747 genes triggered increased biofilm formation in low-pH medium. The observed effects were more striking in a chemically defined medium. We speculate that the SMU.746-SMU.747 complex is responsible for amino acid transport, and we discuss its possible role in colonization and survival in the oral environment.

  4. How to link pyrene to its host lipid to minimize the extent of membrane perturbations and to optimize pyrene dimer formation

    DEFF Research Database (Denmark)

    Franova, M. D.; Repakova, J.; Holopainen, J. M.;

    2014-01-01

    atomistic molecular dynamics simulations to consider membranes where pyrene moieties are attached to lipid acyl chains in varying positions. We find that in a DOPC bilayer the conformational ordering of lipids around di-pyrenyl-PC probes is altered to a largely similar extent regardless of where the pyrene...... moiety is attached to the hydrocarbon chain. This is in contrast to saturated membranes, where pyrene-induced perturbations have been observed to be more prominent. Meanwhile, the formation of pyrene dimers depends on the linkage point between pyrene and its host lipid. Membrane-spanning dimers between...

  5. Temperature and cholera toxin B are factors that influence formation of membrane nanotubes in RT4 and T24 urothelial cancer cell lines

    Directory of Open Access Journals (Sweden)

    Doron Kabaso

    2011-03-01

    Full Text Available Doron Kabaso1*, Maruša Lokar1*, Veronika Kralj-Iglic2, Peter Veranic3, Aleš Iglic11Laboratory of Biophysics, Faculty of Electrical Engineering, 2Laboratory of Clinical Biophysics, Faculty of Medicine, 3Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia; *These two authors equally share the first authorshipAbstract: The growth of membrane nanotubes is crucial for intercellular communication in both normal development and pathological conditions. Therefore, identifying factors that influence their stability and formation are important for both basic research and in development of potential treatments of pathological states. Here we investigate the effect of cholera toxin B (CTB and temperature on two pathological model systems: urothelial cell line RT4, as a model system of a benign tumor, and urothelial cell line T24, as a model system of a metastatic tumor. In particular, the number of intercellular membrane nanotubes (ICNs; ie, membrane nanotubes that bridge neighboring cells was counted. In comparison with RT4 cells, we reveal a significantly higher number in the density of ICNs in T24 cells not derived from RT4 without treatments (P = 0.005, after 20 minutes at room temperature (P = 0.0007, and following CTB treatment (P = 0.000025. The binding of CTB to GM1–lipid complexes in membrane exvaginations or tips of membrane nanotubes may reduce the positive spontaneous (intrinsic curvature of GM1–lipid complexes, which may lead to lipid mediated attractive interactions between CTB–GM1–lipid complexes, their aggregation and consequent formation of enlarged spherical tips of nanotubes. The binding of CTB to GM1 molecules in the outer membrane leaflet of membrane exvaginations and tips of membrane nanotubes may also increase the area difference between the two leaflets and in this way facilitate the growth of membrane nanotubes.Keywords: cancer cells, membrane nanotubes, cholera toxin

  6. New bone formation in a bone defect associated to dental implant using absorbable or non-absorbable membrane in a dog model

    Science.gov (United States)

    Lopez, Maria de Almeida; Olate, Sergio; Lanata-Flores, Antonio; Pozzer, Leandro; Cavalieri-Pereira, Lucas; Cantín, Mario; Vásquez, Bélgica; de Albergaria-Barbosa, José

    2013-01-01

    The aim of this research was to determine the bone formation capacity in fenestration defects associated with dental implants using absorbable and non-absorbable membranes. Six dogs were used in the study. In both tibias of each animal 3 implants were installed, and around these 5 mm circular defects were created. The defects were covered with absorbable membranes (experimental group 1), non-absorbable membranes (experimental group 2), and the third defect was not covered (control group). At 3 and 8 weeks post-surgery, the animals were euthanized and the membranes with the bone tissue around the implants were processed for histological analysis. The statistical analysis was conducted with Tukey’s test, considering statistical significance when p0.1). In the defects without membrane, continuous connective tissue invasions and bone repair deficiency were observed. There were no significant differences in the characteristics and volume of the neoformed bone in the defects around the implants covered by the different membranes, whereas the control defects produced significantly less bone. The use of biological membranes contributes to bone formation in three-wall defects. PMID:24228090

  7. Effects of outer membrane vesicle formation, surface-layer production and nanopod development on the metabolism of phenanthrene by Delftia acidovorans Cs1-4.

    Directory of Open Access Journals (Sweden)

    Ameesha Shetty

    Full Text Available Nanopods are extracellular structures arising from the convergence of two widely distributed bacterial characteristics: production of outer membrane vesicles (OMV and formation of surface layers (S-layers. Nanopod production is driven by OMV formation, and in Delftia acidovorans Cs1-4 growth on phenanthrene induces OMV/nanopod formation. While OMV production has been associated with many functions, particularly with pathogens, linkage to biodegradation has been limited to a membrane stress response to lipophilic compounds. The objectives of this study were to determine: 1. Whether induction of nanopod formation was linked to phenanthrene metabolism or a non-specific membrane stress response, and 2. The relative importance of OMV/nanopod formation vs. formation of the S-layer alone to phenanthrene utilization. Membrane stress response was investigated by quantifying nanopod formation following exposure to compounds that exceeded phenanthrene in membrane stress-inducing potential. Naphthalene did not induce nanopod formation, and toluene was a weak inducer compared to phenanthrene (two- vs. six-fold increase, respectively. Induction of nanopod formation by growth on phenanthrene was therefore linked to phenanthrene metabolism and not a membrane stress response. Impacts on phenanthrene biodegradation of OMV/nanopod production vs. S-layer formation were assessed with D. acidovorans Cs1-4 mutants deficient in S-layer formation or OMV/nanopod production. Both mutants had impaired growth on phenanthrene, but the loss of OMV/nanopod production was more significant than loss of the S-layer. The S-layer of D. acidovorans Cs1-4 did not affect phenanthrene uptake, and its primary role in phenanthrene biodegradation process appeared to be enabling nanopod development. Nanopods appeared to benefit phenanthrene biodegradation by enhancing cellular retention of metabolites. Collectively, these studies established that nanopod/OMV formation was an essential

  8. Effects of outer membrane vesicle formation, surface-layer production and nanopod development on the metabolism of phenanthrene by Delftia acidovorans Cs1-4.

    Science.gov (United States)

    Shetty, Ameesha; Hickey, William J

    2014-01-01

    Nanopods are extracellular structures arising from the convergence of two widely distributed bacterial characteristics: production of outer membrane vesicles (OMV) and formation of surface layers (S-layers). Nanopod production is driven by OMV formation, and in Delftia acidovorans Cs1-4 growth on phenanthrene induces OMV/nanopod formation. While OMV production has been associated with many functions, particularly with pathogens, linkage to biodegradation has been limited to a membrane stress response to lipophilic compounds. The objectives of this study were to determine: 1.) Whether induction of nanopod formation was linked to phenanthrene metabolism or a non-specific membrane stress response, and 2.) The relative importance of OMV/nanopod formation vs. formation of the S-layer alone to phenanthrene utilization. Membrane stress response was investigated by quantifying nanopod formation following exposure to compounds that exceeded phenanthrene in membrane stress-inducing potential. Naphthalene did not induce nanopod formation, and toluene was a weak inducer compared to phenanthrene (two- vs. six-fold increase, respectively). Induction of nanopod formation by growth on phenanthrene was therefore linked to phenanthrene metabolism and not a membrane stress response. Impacts on phenanthrene biodegradation of OMV/nanopod production vs. S-layer formation were assessed with D. acidovorans Cs1-4 mutants deficient in S-layer formation or OMV/nanopod production. Both mutants had impaired growth on phenanthrene, but the loss of OMV/nanopod production was more significant than loss of the S-layer. The S-layer of D. acidovorans Cs1-4 did not affect phenanthrene uptake, and its primary role in phenanthrene biodegradation process appeared to be enabling nanopod development. Nanopods appeared to benefit phenanthrene biodegradation by enhancing cellular retention of metabolites. Collectively, these studies established that nanopod/OMV formation was an essential characteristic of

  9. Two new hyaline-ascospored species of Trichoderma and their phylogenetic positions.

    Science.gov (United States)

    Qin, W T; Zhuang, W Y

    2016-01-01

    Collections of hypocrealean fungi found on decaying wood in subtropical regions of China were examined. Two new species, Trichoderma confluens and T. hubeiense, were discovered and are described. Trichoderma confluens is characterized by its widely effuse to rarely pulvinate, yellow stromata with densely disposed yellowish brown ostioles, simple acremonium- to verticillium-like conidiophores, hyaline conidia and multiform chlamydospores. Trichoderma hubeiense has pulvinate, grayish yellow stromata with brownish ostioles, trichoderma- to verticillium-like conidiophores and hyaline conidia. The phylogenetic positions of the two fungi were investigated based on sequence analyses of RNA polymerase II subunit b and translation elongation factor 1-α genes. The results indicate that T. confluens belongs to the Hypocreanum clade and is associated with but clearly separated from T. applanatum and T. decipiens. Trichoderma hubeiense belongs to the Polysporum clade and related to T. bavaricum but obviously differs from other members of the clade in sequence data. Morphological distinctions between the new species and their close relatives are noted and discussed.

  10. Granular cell tumor of the cecum with extensive hyalinization and calcification: A case report

    Institute of Scientific and Technical Information of China (English)

    Ran Hong; Sung-Chul Lim

    2009-01-01

    A granular cell tumor (GCT) is a benign neoplasm of unclear histogenesis that is generally believed to be of nerve sheath origin. GCT is not common and most often affects the tongue, skin and soft tissue, although it may occur anywhere in the body. We experienced a case of GCT that arose in the cecum of a 55-yearold man. The GCT was removed by laparoscopic resection. In addition to the tumor, endoscopic examination revealed the presence of a 5-mm-polyp in the descending colon and multiple tiny polyps in the sigmoid colon and rectum. Histological examination with a hard consistency; in cut sections, mixed cells with yellowish and whitish portions were seen. The tumor was located between the mucosa and subserosa,and was composed of plump histiocyte-like tumor cells with abundant granular eosinophilic cytoplasm, which were immunoreactive for S-100 protein, vimentin,neuron-specific enolase, inhibin-a and calretinin.The tumor showed extensive hyalinization and focal dystrophic calcification. Immunohistochemical profiles did not confirm any particular cell type for the histogenetic origin of the GCT, including a nerve sheath origin. Extensive hyalinization and calcification showing involution of tumor cells suggest benign clinical behavior of GCT.

  11. Pulmonary hyalinizing granuloma%肺玻璃样变肉芽肿病

    Institute of Scientific and Technical Information of China (English)

    Zhao-lin XU; Drew BETHUNE; Daria MANOS; Annette FOYLE; Harry HENTELEFF; Michael JOHNS-TON; Yannick CARTIER

    2009-01-01

    Objective:To present clinical and pathologic features of pulmonary hyalnizing granuloma through analyzing three cases found in our institution and reviewing cases reported in the English language literature. Methods and Results: Three eases of pulmonary hyalnizing granuloma identified at our institu-tion during the past ten years were reviewed. In the first case, the patient presented with concurrent pulmonary hyalinizing granuloma and histoplasmosis. In the second case, the patient presented with a 5.5 cm lung mass and a separate smaller lesion radiologically resembling bronchogenic carcinoma. There was very prominent polyclonal lymphocytic proliferation at the periphery especially of the smaller lesion likely representing an early stage of the disease process. In the third case, the patient presented with multiple subpleural plaque-like lesions in addition to nodular lesions of the lung. All cases also demonstrated various degrees of lymphocytic infiltration within the lesions. The English literature has been reviewed through searching the PubMed. Conclusion: Since patients with pulmonary hyalinizing granuloma demonstrated a spectrum of clinical presentations, radiologic changes and histologic features with a variety of associated clinical disorders, pulmonary hyalnizing granuloma is more in keeping with a clinicopathologic entity rather than a specific pathologic disease.

  12. Hyaline cartilage involvement in patients with gout and calcium pyrophosphate deposition disease. An ultrasound study.

    Science.gov (United States)

    Filippucci, E; Riveros, M Gutierrez; Georgescu, D; Salaffi, F; Grassi, W

    2009-02-01

    The main aim of the present study was to determine the sensitivity, specificity and accuracy of ultrasonography (US) in detecting monosodium urate and calcium pyrophosphate dihydrate crystals deposits at knee cartilage level using clinical definite diagnosis as standard reference. A total of 32 patients with a diagnosis of gout and 48 patients with pyrophosphate arthropathy were included in the study. Fifty-two patients with rheumatoid arthritis (RA), psoriatic arthritis or osteoarthritis (OA) were recruited as disease controls. All diagnoses were made using an international clinical criterion. US examinations were performed by an experienced sonographer, blind to clinical and laboratory data. Hyaline cartilage was assessed to detect two US findings recently indicated as indicative of crystal deposits: hyperechoic enhancement of the superficial margin of the hyaline cartilage and hyperechoic spots within the cartilage layer not generating a posterior acoustic shadow. Hyperechoic enhancement of the chondrosynovial margin was found in at least one knee of 14 out of 32 (43.7%) patients with gout and in a single knee of only one patient affected by pyrophosphate arthropathy (specificity=99%). Intra-cartilaginous hyperechoic spots were detected in at least one knee of 33 out of 48 (68.7%) patients with pyrophosphate arthropathy and in two disease controls one with OA and the second with RA (specificity=97.6%). The results of the present study indicate that US may play a relevant role in distinguishing cartilage involvement in patients with crystal-related arthropathy. The selected US findings were found to be highly specific.

  13. Talocalcaneal Joint Middle Facet Coalition Resection With Interposition of a Juvenile Hyaline Cartilage Graft.

    Science.gov (United States)

    Tower, Dyane E; Wood, Ryan W; Vaardahl, Michael D

    2015-01-01

    Talocalcaneal joint middle facet coalition is the most common tarsal coalition, occurring in ≤2% of the population. Fewer than 50% of involved feet obtain lasting relief of symptoms after nonoperative treatment, and surgical intervention is commonly used to relieve symptoms, increase the range of motion, improve function, reconstruct concomitant pes planovalgus, and prevent future arthrosis from occurring at the surrounding joints. Several approaches to surgical intervention are available for patients with middle facet coalitions, ranging from resection to hindfoot arthrodesis. We present a series of 4 cases, in 3 adolescent patients, of talocalcaneal joint middle facet coalition resection with interposition of a particulate juvenile hyaline cartilaginous allograft (DeNovo(®) NT Natural Tissue Graft, Zimmer, Inc., Warsaw, IN). With a mean follow-up period of 42.8 ± 2.9 (range 41 to 47) months, the 3 adolescent patients in the present series were doing well with improved subtalar joint motion and decreased pain, and 1 foot showed no bony regrowth on a follow-up computed tomography scan. The use of a particulate juvenile hyaline cartilaginous allograft as interposition material after talocalcaneal middle facet coalition resection combined with adjunct procedures to address concomitant pes planovalgus resulted in good short-term outcomes in 4 feet in 3 adolescent patients. Copyright © 2015 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  14. Sprifermin (rhFGF18) enables proliferation of chondrocytes producing a hyaline cartilage matrix.

    Science.gov (United States)

    Gigout, A; Guehring, H; Froemel, D; Meurer, A; Ladel, C; Reker, D; Bay-Jensen, A C; Karsdal, M A; Lindemann, S

    2017-08-18

    Fibroblast growth factor (FGF) 18 has been shown to increase cartilage volume when injected intra-articularly in animal models of osteoarthritis (OA) and in patients with knee OA (during clinical development of the recombinant human FGF18, sprifermin). However, the exact nature of this effect is still unknown. In this study, we aimed to investigate the effects of sprifermin at the cellular level. A combination of different chondrocyte culture systems was used and the effects of sprifermin on proliferation, the phenotype and matrix production were evaluated. The involvement of MAPKs in sprifermin signalling was also studied. In monolayer, we observed that sprifermin promoted a round cell morphology and stimulated both cellular proliferation and Sox9 expression while strongly decreasing type I collagen expression. In 3D culture, sprifermin increased the number of matrix-producing chondrocytes, improved the type II:I collagen ratio and enabled human OA chondrocytes to produce a hyaline extracellular matrix (ECM). Furthermore, we found that sprifermin displayed a 'hit and run' mode of action, with intermittent exposure required for the compound to fully exert its anabolic effect. Finally, sprifermin appeared to signal through activation of ERK. Our results indicate that intermittent exposure to sprifermin leads to expansion of hyaline cartilage-producing chondrocytes. These in vitro findings are consistent with the increased cartilage volume observed in the knees of OA patients after intra-articular injection with sprifermin in clinical studies. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. Superficial Dermal Fibroblasts Enhance Basement Membrane and Epidermal Barrier Formation in Tissue-Engineered Skin: Implications for Treatment of Skin Basement Membrane Disorders

    OpenAIRE

    2013-01-01

    Basement membrane is a highly specialized structure that binds the dermis and the epidermis of the skin, and is mainly composed of laminins, nidogen, collagen types IV and VII, and the proteoglycans, collagen type XVIII and perlecan, all of which play critical roles in the function and resilience of skin. Both dermal fibroblasts and epidermal keratinocytes contribute to the development of the basement membrane, and in turn the basement membrane and underlying dermis influence the development ...

  16. Formation of a Bazooka-Stardust complex is essential for plasma membrane polarity in epithelia.

    Science.gov (United States)

    Krahn, Michael P; Bückers, Johanna; Kastrup, Lars; Wodarz, Andreas

    2010-09-01

    Apical-basal polarity in Drosophila melanogaster epithelia depends on several evolutionarily conserved proteins that have been assigned to two distinct protein complexes: the Bazooka (Baz)-PAR-6 (partitioning defective 6)-atypical protein kinase C (aPKC) complex and the Crumbs (Crb)-Stardust (Sdt) complex. These proteins operate in a functional hierarchy, in which Baz is required for the proper subcellular localization of all other proteins. We investigated how these proteins interact and how this interaction is regulated. We show that Baz recruits Sdt to the plasma membrane by direct interaction between the Postsynaptic density 95/Discs large/Zonula occludens 1 (PDZ) domain of Sdt and a region of Baz that contains a phosphorylation site for aPKC. Phosphorylation of Baz causes the dissociation of the Baz-Sdt complex. Overexpression of a nonphosphorylatable version of Baz blocks the dissociation of Sdt from Baz, causing phenotypes very similar to those of crb and sdt mutations. Our findings provide a molecular mechanism for the phosphorylation-dependent interaction between the Baz-PAR-3 and Crb complexes during the establishment of epithelial polarity.

  17. Formation of helical membrane tubes around microtubules by single-headed kinesin KIF1A

    Science.gov (United States)

    Oriola, David; Roth, Sophie; Dogterom, Marileen; Casademunt, Jaume

    2015-08-01

    The kinesin-3 motor KIF1A is in charge of vesicular transport in neuronal axons. Its single-headed form is known to be very inefficient due to the presence of a diffusive state in the mechanochemical cycle. However, recent theoretical studies have suggested that these motors could largely enhance force generation by working in teams. Here we test this prediction by challenging single-headed KIF1A to extract membrane tubes from giant vesicles along microtubule filaments in a minimal in vitro system. Remarkably, not only KIF1A motors are able to extract tubes but they feature a novel phenomenon: tubes are wound around microtubules forming tubular helices. This finding reveals an unforeseen combination of cooperative force generation and self-organized manoeuvreing capability, suggesting that the diffusive state may be a key ingredient for collective motor performance under demanding traffic conditions. Hence, we conclude that KIF1A is a genuinely cooperative motor, possibly explaining its specificity to axonal trafficking.

  18. Sunlight-Driven Hydrogen Formation by Membrane-Supported Photoelectrochemical Water Splitting

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Nathan S. [California Institute of Technology

    2014-03-26

    This report describes the significant advances in the development of the polymer-supported photoelectrochemical water-splitting system that was proposed under DOE grant number DE-FG02-05ER15754. We developed Si microwire-array photoelectrodes, demonstrated control over the material and light-absorption properties of the microwire-array photoelectrodes, developed inexpensive processes for synthesizing the arrays, and doped the arrays p-type for use as photocathodes. We also developed techniques for depositing metal-nanoparticle catalysts of the hydrogen-evolution reaction (HER) on the wire arrays, investigated the stability and catalytic performance of the nanoparticles, and demonstrated that Ni-Mo alloys are promising earth-abundant catalysts of the HER. We also developed methods that allow reuse of the single-crystalline Si substrates used for microwire growth and methods of embedding the microwire photocathodes in plastic to enable large-scale processing and deployment of the technology. Furthermore we developed techniques for controlling the structure of WO3 films, and demonstrated that structural control can improve the quantum yield of photoanodes. Thus, by the conclusion of this project, we demonstrated significant advances in the development of all components of a sunlight-driven membrane-supported photoelectrochemical water-splitting system. This final report provides descriptions of some of the scientific accomplishments that were achieved under the support of this project and also provides references to the peer-reviewed publications that resulted from this effort.

  19. In-situ formation of solidified hydrogen thin-membrane targets using a pulse tube cryocooler

    Science.gov (United States)

    Astbury, S.; Bedacht, S.; Brummitt, P.; Carroll, D.; Clarke, R.; Crisp, S.; Hernandez-Gomez, C.; Holligan, P.; Hook, S.; Merchan, J. S.; Neely, D.; Ortner, A.; Rathbone, D.; Rice, P.; Schaumann, G.; Scott, G.; Spindloe, C.; Spurdle, S.; Tebartz, A.; Tomlinson, S.; Wagner, F.; Borghesi, M.; Roth, M.; Tolley, M. K.

    2016-04-01

    An account is given of the Central Laser Facility's work to produce a cryogenic hydrogen targetry system using a pulse tube cryocooler. Due to the increasing demand for low Z thin laser targets, CLF (in collaboration with TUD) have been developing a system which allows the production of solid hydrogen membranes by engineering a design which can achieve this remotely; enabling the gas injection, condensation and solidification of hydrogen without compromising the vacuum of the target chamber. A dynamic sealing mechanism was integrated which allows targets to be grown and then remotely exposed to open vacuum for laser interaction. Further research was conducted on the survivability of the cryogenic targets which concluded that a warm gas effect causes temperature spiking when exposing the solidified hydrogen to the outer vacuum. This effect was shown to be mitigated by improving the pumping capacity of the environment and reducing the minimum temperature obtainable on the target mount. This was achieved by developing a two-stage radiation shield encased with superinsulating blanketing; reducing the base temperature from 14 ± 0.5 K to 7.2 ± 0.2 K about the coldhead as well as improving temperature control stability following the installation of a high-performance temperature controller and sensor apparatus. The system was delivered experimentally and in July 2014 the first laser shots were taken upon hydrogen targets in the Vulcan TAP facility.

  20. Fluorescence detection of lipid-induced oligomeric intermediates involved in lysozyme "amyloid-like" fiber formation driven by anionic membranes.

    Science.gov (United States)

    Melo, Ana M; Ricardo, Joana C; Fedorov, Aleksander; Prieto, Manuel; Coutinho, Ana

    2013-03-14

    Recent findings implicate that "amyloid-like" fiber formation by several non-amyloidogenic proteins/peptides can be triggered by negatively charged lipid membranes. In order to elucidate the factors that govern the formation of these structures, the interaction of lysozyme with phosphatidylserine-containing lipid vesicles was studied by steady-state and time-resolved fluorescence measurements. Three consecutive stages in the interaction of Alexa488-fluorescently labeled lysozyme (Lz-A488) with acidic lipid vesicles were identified in ensemble average measurements. The variation of the mean fluorescence lifetime of Lz-A488 as a function of the surface coverage of the liposomes was quantitatively described by a cooperative partition model that assumes that monomeric lysozyme molecules partition into the bilayer surface and reversibly assemble into oligomers with k subunits (k ≥ 6). The global fit to the experimental data covering a wide range of experimental conditions was performed by taking into account electrostatic effects by means of the Gouy-Chapman theory using a single self-consistent pair of parameters (aggregation constant and stoichiometry). The lipid-protein supramolecular assemblies formed at a low lipid/protein molar ratio were further characterized by fluorescence lifetime imaging microscopy at the single-fiber level, which reported that quenched oligomers are the predominant species in these structures.

  1. Heterodimer formation between c-Jun and Jun B proteins mediated by Epstein Barr virus encoded latent membrane protein 1

    Institute of Scientific and Technical Information of China (English)

    SONG Xin; TAO Yongguang; TAN Yunnian; Leo M. Lee; DENG Xiyun; WU Qiao; CAO Ya

    2005-01-01

    Epstein-Barr virus (EBV) encoded latent membrane protein 1 (LMP1) may trigger the transcription factor AP-1 including c-Jun and c-fos. In this report, using a Tet-on LMP1 HNE2 cell line which is a dual-stable LMP1 integrated nasopharyngeal carcinoma (NPC) cell line and the expression of LMP1 in which could be regulated by the Tet-on system, we show that Jun B can efficiently form a new heterodimeric complex with the c-Jun protein under the regulation of LMP1, phosphorylation of c-Jun (ser 63, ser 73) and Jun B is involved in the process of the new heterodimeric formation. We also find that this heterodimeric form can bind to the AP-1 consensus sequence. Transfection studies suggest that JNK interaction protein (JIP) could inhibit the heterodimer formation of c-Jun and Jun B through blocking the AP-1 signaling pathway triggered by LMP1. The interaction and function between c-Jun protein and Jun B protein increase the repertoire of possible regulatory complexes by LMP1 that could play an important role in the regulation of transcription of specific cellular genes in the process of genesis of nasopharyngeal carcinoma.

  2. Key molecular requirements for raft formation in lipid/cholesterol membranes.

    Directory of Open Access Journals (Sweden)

    Davit Hakobyan

    Full Text Available The lipid mixture of DPPC (saturated lipid/DUPC (unsaturated lipid/CHOL (cholesterol is studied with respect to its ability to form liquid-ordered and liquid-disordered phases. We employ coarse-grained simulations with MARTINI force field. All three components are systematically modified in order to explore the relevant molecular properties, leading to phase separation. Specifically, we show that the DPPC/DUPC/CHOL system unmixes due to enthalpic DPPC-DPPC and DPPC-CHOL interactions. The phase separation remains unchanged, except for the formation of a gel phase at long times after decreasing the conformational degrees of freedom of the unsaturated DUPC. In contrast, the phase separation can be suppressed by softening the DPPC chains. In an attempt to mimic the ordering and unmixing effect of CHOL the latter is replaced by a stiff and shortened DPPC-like lipid. One still observes phase separation, suggesting that it is mainly the rigid and planar structure of CHOL which is important for raft formation. Addition of an extra bead to the head of CHOL has no notable impact on the phase separation of the system, supporting the irrelevance of the Umbrella model for the phase separation. Reduction of the conformational entropy of CHOL by stiffening its last bead results in a significant increase of the order of the DPPC/CHOL domain. This suggests that the conformational entropy of CHOL is important to prohibit the gelation process. The interleaflet interactions as mediated by the terminal molecular groups seem to have a strong impact on the possibility of a subsequent gelation process after phase separation.

  3. Arabidopsis membrane-associated acyl-CoA-binding protein ACBP1 is involved in stem cuticle formation.

    Science.gov (United States)

    Xue, Yan; Xiao, Shi; Kim, Juyoung; Lung, Shiu-Cheung; Chen, Liang; Tanner, Julian A; Suh, Mi Chung; Chye, Mee-Len

    2014-10-01

    The membrane-anchored Arabidopsis thaliana ACYL-COA-BINDING PROTEIN1 (AtACBP1) plays important roles in embryogenesis and abiotic stress responses, and interacts with long-chain (LC) acyl-CoA esters. Here, AtACBP1 function in stem cuticle formation was investigated. Transgenic Arabidopsis transformed with an AtACBP1pro::GUS construct revealed β-glucuronidase (GUS) expression on the stem (but not leaf) surface, suggesting a specific role in stem cuticle formation. Isothermal titration calorimetry results revealed that (His)6-tagged recombinant AtACBP1 interacts with LC acyl-CoA esters (18:1-, 18:2-, and 18:3-CoAs) and very-long-chain (VLC) acyl-CoA esters (24:0-, 25:0-, and 26:0-CoAs). VLC fatty acids have been previously demonstrated to act as precursors in wax biosynthesis. Gas chromatography (GC)-flame ionization detector (FID) and GC-mass spectrometry (MS) analyses revealed that an acbp1 mutant showed a reduction in stem and leaf cuticular wax and stem cutin monomer composition in comparison with the wild type (Col-0). Consequently, the acbp1 mutant showed fewer wax crystals on the stem surface in scanning electron microscopy and an irregular stem cuticle layer in transmission electron microscopy in comparison with the wild type. Also, the mutant stems consistently showed a decline in expression of cuticular wax and cutin biosynthetic genes in comparison with the wild type, and the mutant leaves were more susceptible to infection by the necrotrophic pathogen Botrytis cinerea. Taken together, these findings suggest that AtACBP1 participates in Arabidopsis stem cuticle formation by trafficking VLC acyl-CoAs.

  4. A mechanism for the polarity formation of chemoreceptors at the growth cone membrane for gradient amplification during directional sensing.

    Directory of Open Access Journals (Sweden)

    Cedric Bouzigues

    Full Text Available Accurate response to external directional signals is essential for many physiological functions such as chemotaxis or axonal guidance. It relies on the detection and amplification of gradients of chemical cues, which, in eukaryotic cells, involves the asymmetric relocalization of signaling molecules. How molecular events coordinate to induce a polarity at the cell level remains however poorly understood, particularly for nerve chemotaxis. Here, we propose a model, inspired by single-molecule experiments, for the membrane dynamics of GABA chemoreceptors in nerve growth cones (GCs during directional sensing. In our model, transient interactions between the receptors and the microtubules, coupled to GABA-induced signaling, provide a positive-feedback loop that leads to redistribution of the receptors towards the gradient source. Using numerical simulations with parameters derived from experiments, we find that the kinetics of polarization and the steady-state polarized distribution of GABA receptors are in remarkable agreement with experimental observations. Furthermore, we make predictions on the properties of the GC seen as a sensing, amplification and filtering module. In particular, the growth cone acts as a low-pass filter with a time constant approximately 10 minutes determined by the Brownian diffusion of chemoreceptors in the membrane. This filtering makes the gradient amplification resistant to rapid fluctuations of the external signals, a beneficial feature to enhance the accuracy of neuronal wiring. Since the model is based on minimal assumptions on the receptor/cytoskeleton interactions, its validity extends to polarity formation beyond the case of GABA gradient sensing. Altogether, it constitutes an original positive-feedback mechanism by which cells can dynamically adapt their internal organization to external signals.

  5. The Pathogenic A116V Mutation Enhances Ion-Selective Channel Formation by Prion Protein in Membranes.

    Science.gov (United States)

    Sabareesan, Ambadi Thody; Singh, Jogender; Roy, Samrat; Udgaonkar, Jayant B; Mathew, M K

    2016-04-26

    Prion diseases are a group of fatal neurodegenerative disorders that afflict mammals. Misfolded and aggregated forms of the prion protein (PrP(Sc)) have been associated with many prion diseases. A transmembrane form of PrP favored by the pathogenic mutation A116V is associated with Gerstmann-Sträussler-Scheinker syndrome, but no accumulation of PrP(Sc) is detected. However, the role of the transmembrane form of PrP in pathological processes leading to neuronal death remains unclear. This study reports that the full-length mouse PrP (moPrP) significantly increases the permeability of living cells to K(+), and forms K(+)- and Ca(2+)-selective channels in lipid membranes. Importantly, the pathogenic mutation A116V greatly increases the channel-forming capability of moPrP. The channels thus formed are impermeable to sodium and chloride ions, and are blocked by blockers of voltage-gated ion channels. Hydrogen-deuterium exchange studies coupled with mass spectrometry (HDX-MS) show that upon interaction with lipid, the central hydrophobic region (109-132) of the protein is protected against exchange, making it a good candidate for inserting into the membrane and lining the channel. HDX-MS also shows a dramatic increase in the protein-lipid stoichiometry for A116V moPrP, providing a rationale for its increased channel-forming capability. The results suggest that ion channel formation may be a possible mechanism of PrP-mediated neurodegeneration by the transmembrane forms of PrP.

  6. 'Should I stay or should I go?' Bacterial attachment vs biofilm formation on surface-modified membranes.

    Science.gov (United States)

    Bernstein, Roy; Freger, Viatcheslav; Lee, Jin-Hyung; Kim, Yong-Guy; Lee, Jintae; Herzberg, Moshe

    2014-01-01

    A number of techniques are used for testing the anti-biofouling activity of surfaces, yet the correlation between different results is often questionable. In this report, the correlation between initial bacterial deposition (fast tests, reported previously) and biofilm growth (much slower tests) was analyzed on a pristine and a surface-modified reverse osmosis membrane ESPA-1. The membrane was modified with grafted hydrophilic polymers bearing negatively charged, positively charged and zwitter-ionic moieties. Using three different bacterial strains it was found that there was no general correlation between the initial bacterial deposition rates and biofilm growth on surfaces, the reasons being different for each modified surface. For the negatively charged surface the slowest deposition due to the charge repulsion was eventually succeeded by the largest biofilm growth, probably due to secretion of extracellular polymeric substances (EPS) that mediated a strong attachment. For the positively charged surface, short-term charge attraction by quaternary amine groups led to the fastest deposition, but could be eventually overridden by their antimicrobial activity, resulting in non-consistent results where in some cases a lower biofilm formation rate was observed. The results indicate that initial deposition rates have to be used and interpreted with great care, when used for assessing the anti-biofouling activity of surfaces. However, for a weakly interacting 'low-fouling' zwitter-ionic surface, the positive correlation between initial cell deposition and biofilm growth, especially under flow, suggests that for this type of coating initial deposition tests may be fairly indicative of anti-biofouling potential.

  7. Bacoside-A, an anti-amyloid natural substance, inhibits membrane disruption by the amyloidogenic determinant of prion protein through accelerating fibril formation.

    Science.gov (United States)

    Malishev, Ravit; Nandi, Sukhendu; Kolusheva, Sofiya; Shaham-Niv, Shira; Gazit, Ehud; Jelinek, Raz

    2016-09-01

    Bacosides, class of compounds extracted from the Bacopa monniera plant, exhibit interesting therapeutic properties, particularly enhancing cognitive functions and putative anti-amyloid activity. We show that bacoside-A exerted significant effects upon fibrillation and membrane interactions of the amyloidogenic fragment of the prion protein [PrP(106-126)]. Specifically, when co-incubated with PrP(106-126), bacoside-A accelerated fibril formation in the presence of lipid bilayers and in parallel inhibited bilayer interactions of the peptide aggregates formed in solution. These interesting phenomena were studied by spectroscopic and microscopic techniques, which suggest that bacoside A-promoted fibrillation reduced the concentration of membrane-active pre-fibrillar species of the prion fragment. This study suggests that induction of fibril formation and corresponding inhibition of membrane interactions are likely the underlying factors for ameliorating amyloid protein toxicity by bacoside-A.

  8. Formation and evaluation of semi-IPN of nafion 117 membrane for direct methanol fuel cell. 1. Crosslinked sulfonated polystyrene in the pores of nafion 117

    Science.gov (United States)

    Kundu, P. P.; Kim, Beom Taek; Ahn, Ji Eun; Han, Hak Soo; Shul, Yong Gun

    The in situ polymerization and crosslinking of sodium salt of sulfonated styrene in the pores of nafion 117 membrane has been studied for the evaluation of electrical performance of the resultant semi-IPN (semi-interpenetrating polymer network) membrane in direct methanol fuel cell (DMFC). The formation of semi-IPN is confirmed from the presence of aromatic characteristics peak in the FTIR spectra. Impedance results indicate that the semi-IPN sample with higher water uptake exhibits lower interfacial resistance compared to a sample with water uptake. This indicates that the semi-IPN formed in the pores of nafion 117 membrane has the ability to reduce methanol crossover by blocking the transportation. At higher temperatures (>110 °C) and lower current density (<25 mA cm -2), the electrical performance (power density) of a DMFC with a representative semi-IPN sample is observed to be higher than that with a nafion membrane.

  9. Osseous oral hyaline ring granuloma mimicking a mandible tumor in a child with congenital agenesis of the corpus callosum

    Science.gov (United States)

    Neves-Silva, Rodrigo; Ferreira-Gomes, Camilla-Borges; Palmier, Natalia; Brum-Corrêa, Marcelo; Paes-Almeida, Oslei; Ajudarte-Lopes, Marcio; Agustin-Vargas, Pablo

    2017-01-01

    Background Hyaline ring granuloma (HRG) of the oral cavity is an uncommon disorder considered to be a foreign-body reaction resulting from implantation of food vegetable particles. Microscopically, it is characterized by the presence of structures of hyaline rings in an inflamed fibrous tissue background, which contains multinucleated giant cells. Material and Methods We present the case of a 4-year-old boy diagnosed with a mandible osseous HRG, which showed clinical and tomographic aspects suggestive of an aggressive bone tumor. Results The patient underwent surgical exploration and histopathologic analysis showed fragments composed predominantly of widespread dense connective tissue with an acute and chronic inflammatory infiltrate containing multinucleated giant cells and scattered areas of eosinophilic material associated with hyaline rings, strongly suggestive of vegetable particles. The eosinophilic material was positive for periodic acid-Schiff (PAS) and resistant to diastase digestion. These features led to diagnosis of osseous HRG. Scanning electron microscopy (SEM) analysis was performed for illustrative purposes and the multiple structures resembling vegetable particles were characterized in more detail. Conclusions Although rare, this case highlights the importance of the clinician’s awareness regarding the existence of an osseous counterpart of HRG. Key words:Agenesis of the corpus callosum, child, hyaline ring granuloma, intraosseous, mandible, pulse granuloma. PMID:28210458

  10. Regeneration of hyaline-like cartilage in situ with SOX9 stimulation of bone marrow-derived mesenchymal stem cells.

    Science.gov (United States)

    Zhang, Xiaowei; Wu, Shili; Naccarato, Ty; Prakash-Damani, Manan; Chou, Yuan; Chu, Cong-Qiu; Zhu, Yong

    2017-01-01

    Microfracture, a common procedure for treatment of cartilage injury, induces fibrocartilage repair by recruiting bone marrow derived mesenchymal stem cells (MSC) to the site of cartilage injury. However, fibrocartilage is inferior biomechanically to hyaline cartilage. SRY-type high-mobility group box-9 (SOX9) is a master regulator of chondrogenesis by promoting proliferation and differentiation of MSC into chondrocytes. In this study we aimed to test the therapeutic potential of cell penetrating recombinant SOX9 protein in regeneration of hyaline cartilage in situ at the site of cartilage injury. We generated a recombinant SOX9 protein which was fused with super positively charged green fluorescence protein (GFP) (scSOX9) to facilitate cell penetration. scSOX9 was able to induce chondrogenesis of bone marrow derived MSC in vitro. In a rabbit cartilage injury model, scSOX9 in combination with microfracture significantly improved quality of repaired cartilage as shown by macroscopic appearance. Histological analysis revealed that the reparative tissue induced by microfracture with scSOX9 had features of hyaline cartilage; and collagen type II to type I ratio was similar to that in normal cartilage. This short term in vivo study demonstrated that when administered at the site of microfracture, scSOX9 was able to induce reparative tissue with features of hyaline cartilage.

  11. Fibrous cartilage of human menisci is less shock-absorbing and energy-dissipating than hyaline cartilage.

    Science.gov (United States)

    Gaugler, Mario; Wirz, Dieter; Ronken, Sarah; Hafner, Mirjam; Göpfert, Beat; Friederich, Niklaus F; Elke, Reinhard

    2015-04-01

    To test meniscal mechanical properties such as the dynamic modulus of elasticity E* and the loss angle δ at two loading frequencies ω at different locations of the menisci and compare it to E* and δ of hyaline cartilage in indentation mode with spherical indenters. On nine pairs of human menisci, the dynamic E*-modulus and loss angle δ (as a measure of the energy dissipation) were determined. The measurements were performed at two different strain rates (slow sinusoidal and fast single impact) to show the strain rate dependence of the material. The measurements were compared to previous similar measurements with the same equipment on human hyaline cartilage. The resultant E* at fast indentation (median 1.16 MPa) was significantly higher, and the loss angle was significantly lower (median 10.2°) compared to slow-loading mode's E* and δ (median 0.18 MPa and 16.9°, respectively). Further, significant differences for different locations are shown. On the medial meniscus, the anterior horn shows the highest resultant dynamic modulus. In dynamic measurements with a spherical indenter, the menisci are much softer and less energy-dissipating than hyaline cartilage. Further, the menisci are stiffer and less energy-dissipating in the middle, intermediate part compared to the meniscal base. In compression, the energy dissipation of meniscus cartilage plays a minor role compared to hyaline cartilage. At high impacts, energy dissipation is less than on low impacts, similar to cartilage.

  12. Distinction between the extracellular matrix of the nucleus pulposus and hyaline cartilage: a requisite for tissue engineering of intervertebral disc

    Directory of Open Access Journals (Sweden)

    Mwale F.

    2004-12-01

    Full Text Available Tissue engineering of intervertebral discs (IVD using mesenchymal stem cells (MSCs induced to differentiate into a disc-cell phenotype has been considered as an alternative treatment for disc degeneration. However, since there is no unique marker characteristic of discs and since hyaline cartilage and immature nucleus pulposus (NP possess similar macromolecules in their extracellular matrix, it is currently difficult to recognize MSC conversion to a disc cell. This study was performed to compare the proteoglycan to collagen ratio (measured as GAG to hydroxyproline ratio in the NP of normal disc to that of the hyaline cartilage of the endplate within the same group of individuals and test the hypothesis that this ratio can be used for in vivo studies to distinguish between a normal NP and hyaline cartilage phenotype. Whole human lumbar spine specimens from fresh cadavers, ranging in age from 12 weeks to 79 years, were used to harvest the IVDs and adjacent endplates. The GAG to hydroxyproline ratio within the NP of young adults is approximately 27:1, whereas the ratio within the hyaline cartilage endplate of the same aged individuals is about 2:1. The production of an extracellular matrix with a high proteoglycan to collagen ratio can be used in vivo to distinguish NP cells from chondrocytes, and could help in identifying a NP-like phenotype in vivo as opposed to a chondrocyte when MSCs are induced to differentiate for tissue engineering of a disc.

  13. Similar hyaline-like cartilage repair of osteochondral defects in rabbits using isotropic and anisotropic collagen scaffolds.

    Science.gov (United States)

    de Mulder, Eric L W; Hannink, Gerjon; van Kuppevelt, Toin H; Daamen, Willeke F; Buma, Pieter

    2014-02-01

    Lesions in knee joint articular cartilage (AC) have limited repair capacity. Many clinically available treatments induce a fibrous-like cartilage repair instead of hyaline cartilage. To induce hyaline cartilage repair, we hypothesized that type I collagen scaffolds with fibers aligned perpendicular to the AC surface would result in qualitatively better tissue repair due to a guided cellular influx from the subchondral bone. By specific freezing protocols, type I collagen scaffolds with isotropic and anisotropic fiber architectures were produced. Rabbits were operated on bilaterally and two full thickness defects were created in each knee joint. The defects were filled with (1) an isotropic scaffold, (2) an anisotropic scaffold with pores parallel to the cartilage surface, and (3) an anisotropic scaffold with pores perpendicular to the cartilage surface. Empty defects served as controls. After 4 (n=13) and 12 (n=13) weeks, regeneration was scored qualitatively and quantitatively using histological analysis and a modified O'Driscoll score. After 4 weeks, all defects were completely filled with partially differentiated hyaline cartilage tissue. No differences in O'Driscoll scores were measured between empty defects and scaffold types. After 12 weeks, all treatments led to hyaline cartilage repair visualized by increased glycosaminoglycan staining. Total scores were significantly increased for parallel anisotropic and empty defects over time (phyaline-like cartilage repair. Fiber architecture had no effect on cartilage repair.

  14. The Role of Amines, Hydrogen Sulfide and Carbon Dioxide in the Formation of Prebiotic Macromolecules Surrounded by Membranes

    Science.gov (United States)

    Rajen, Gaurav

    2016-04-01

    Amphiphilic compounds are known to self-assemble into membranous structures when exposed to alternate dry and wet conditions. This paper presents a model of how such structures could form near hydrothermal vents while containing macromolecules such as amino acids. The formation of amino acids near deep ocean hydrothermal vents as precursors for the origins of life is problematic as amino acids degrade from thermal energy. In the model proposed here, amino acids would degrade into amines (near hydrothermal vents). Amines have an affinity to interact with carbon dioxide (CO2) and hydrogen sulfide (H2S), form weak heat-unstable salts, and then through exposure to thermal energy release the acid gases and regenerate back to amines. Amines carrying and releasing H2S and CO2 would help other macromolecules form along with amino acids within protected cell-like structures; the cyclical release and recapture of acid gases would subsequently help the amino acids form bonds; further thermal action would degrade some of the amines into polymers that provide more strength and rigidity to the membrane walls; and also enable escaping gases to form tubes within the surrounding membranes for inlet and outlet of chemicals. Consider that liquids and gases are undergoing thermal convection inside a porous medium, and the convecting liquids contain some amines. Consider now that an amine weak salt carrying H2S and another carrying CO2 is inside a vesicle that formed through self-assembly. As this vesicle moves around in the thermal convection cell it will come close to the heat source and release the H2S and CO2 inside the vesicle. As the vesicle moves away from the heat source, the gases would be reabsorbed into the amines. This process would create stability and a repeating set of reactions, reactants, and products forming and reforming - cyclical stability is a key criterion for more complex reactions to occur. Some of the amines present would reform into an amino acid (as occurs

  15. Interface Symbiotic Membrane Formation in Root Nodules of Medicago truncatula: the Role of Synaptotagmins MtSyt1, MtSyt2 and MtSyt3

    Science.gov (United States)

    Gavrin, Aleksandr; Kulikova, Olga; Bisseling, Ton; Fedorova, Elena E.

    2017-01-01

    Symbiotic bacteria (rhizobia) are maintained and conditioned to fix atmospheric nitrogen in infected cells of legume root nodules. Rhizobia are confined to the asymmetrical protrusions of plasma membrane (PM): infection threads (IT), cell wall-free unwalled droplets and symbiosomes. These compartments rapidly increase in surface and volume due to the microsymbiont expansion, and remarkably, the membrane resources of the host cells are targeted to interface membrane quite precisely. We hypothesized that the change in the membrane tension around the expanding microsymbionts creates a vector for membrane traffic toward the symbiotic interface. To test this hypothesis, we selected calcium sensors from the group of synaptotagmins: MtSyt1, Medicago truncatula homolog of AtSYT1 from Arabidopsis thaliana known to be involved in membrane repair, and two other homologs expressed in root nodules: MtSyt2 and MtSyt3. Here we show that MtSyt1, MtSyt2, and MtSyt3 are expressed in the expanding cells of the meristem, zone of infection and proximal cell layers of zone of nitrogen fixation (MtSyt1, MtSyt3). All three GFP-tagged proteins delineate the interface membrane of IT and unwalled droplets and create a subcompartments of PM surrounding these structures. The localization of MtSyt1 by EM immunogold labeling has shown the signal on symbiosome membrane and endoplasmic reticulum (ER). To specify the role of synaptotagmins in interface membrane formation, we compared the localization of MtSyt1, MtSyt3 and exocyst subunit EXO70i, involved in the tethering of post-Golgi secretory vesicles and operational in tip growth. The localization of EXO70i in root nodules and arbusculated roots was strictly associated with the tips of IT and the tips of arbuscular fine branches, but the distribution of synaptotagmins on membrane subcompartments was broader and includes lateral parts of IT, the membrane of unwalled droplets as well as the symbiosomes. The double silencing of synaptotagmins

  16. Hyaline Tintinnina (Protozoa-Ciliophora-Oligotrichida from northeast Brazilian coastal reefs

    Directory of Open Access Journals (Sweden)

    Roberto Sassi

    1989-01-01

    Full Text Available Seven species of hyaline Tintinnina were obtained from plankton samples collected near the coastal reefs of Ponta do Seixas (Lat. 7º09'16"S, Long. 34º4735"W, Northeastern Brazil, from April 1981 to May 1982 and from April 1983 to May 1984: Amphorellopsis acuta (Schmidt, 1901, Dadayiella ganymedes (Entz Sr., 1884, Epiplocyloides reticulata (Ostenfeld & Schmidt, 1901, Eutintinnus tubulosus (Ostenfeld, 1899, Favella ehrenbergi (Claparède & Lachmann, 1858, Metacylis mereschkowskyi Kofoid & Campbell, 1929 and M. perspicax (Hada, 1938. The most frequent and abundant species were M. mereschkowskyi and F. ehrenbergi. Except/.ganymedes, E. reticulata and F. ehrenbergi all species are new records from Brazil. Metacylis perspicax is also the seventh world register. For all species we provide description, drawings, measurements, seasonal occurrence, world distribution and some systematic comments.

  17. [Biomechanical properties (compressive strength and compressive pressure at break) of hyaline cartilage under axial load].

    Science.gov (United States)

    Spahn, G; Wittig, R

    2003-01-01

    Explanations concerning the physical properties of hyaline cartilage are different. It was the intention of this study to determine the material parameters of hyaline cartilage under axial load (elasticity, plasticity, elasticity and module pressure stress to break). Specimens from the medial femoral condyle (chondro-cortical ships) from adult female domestic pigs (n=28) were used for the experiments. The specimens were completely embedded in plaster to minimize shearing. Axial load was carried out by an universal mechanical testing machine (Zwick Z2.5/TS1S, Ulm, Germany) to determine elastic and plastic deformation and pressure stress to break. Axial load up to 5 MPa produces an almost elastic deformation, an increasing axial load results in a plastic deformation. In the range of 3 to 5 MPa the principle of Hooke is valid. The elasticity module amounted to 39.2 +/- 11.9 N/mm(2), determined under 3.8 MPa axial load. An axial load of 25.8 +/- 5.2 MPa (sigma max ) causes a break of cartilage. A strong correlation between break resistance and thickness of the chondral slice (r=0.71; p .05) was observed. The low module of chondral elasticity characterizes this tissue as "soft". Moderate axial load causes an ideal elastic, higher axial load a plastic deformation. The medium pressure to break to amounted 25.8 MPa. The medium pressure to break of 25.8 MPa is comparable with the forces produced by an unrestrained limited downfall from a height of 4.3 m. It must be concluded that isolated chondral fractures are rare consequences of a trauma as long as accompanying ligamentous or osseous damages are not found.

  18. Ultrasonography shows disappearance of monosodium urate crystal deposition on hyaline cartilage after sustained normouricemia is achieved.

    Science.gov (United States)

    Thiele, Ralf G; Schlesinger, Naomi

    2010-02-01

    This study aimed at determining whether lowering serum urate (SU) to less than 6 mg/dl in patients with gout affects ultrasonographic findings. Seven joints in five patients with monosodium urate (MSU) crystal proven gout and hyperuricemia were examined over time with serial ultrasonography. Four of the five patients were treated with urate lowering drugs (ULDs) (allopurinol, n = 3; probenecid, n = 1). One patient was treated with colchicine alone. Attention was given to changes in a hyperechoic, irregular coating of the hyaline cartilage in the examined joints (double contour sign or "urate icing"). This coating was considered to represent precipitate of MSU crystals. Index joints included metacarpophalangeal (MCP) joints (n = 2), knee joints (n = 3), and first metatarsophalangeal (MTP) joints (n = 2). The interval between baseline and follow-up images ranged from 7 to 18 months. Serial SU levels were obtained during the follow-up period. During the follow-up period, three patients treated with ULD (allopurinol, n = 2; probenecid, n = 1) achieved a SU level of or =7 mg/dl. In one patient treated with allopurinol, SU levels improved from 13 to 7 mg/dl during the follow-up period. Decrease, but not resolution of the hyperechoic coating was seen in this patient. In the patient treated with colchicine alone, SU levels remained >8 mg/dl, and no sonographic change was observed. In our patients, sonographic signs of deposition of MSU crystals on the surface of hyaline cartilage disappeared completely if sustained normouricemia was achieved. This is the first report showing that characteristic sonographic changes are influenced by ULDs once SU levels remain < or =6 mg/dl for 7 months or more. Sonographic changes of gout correlate with SU levels and may be a non-invasive means to track changes in the uric acid pool. Larger prospective studies are needed to further assess these potentially important findings.

  19. Real-time UV-visible spectroscopy analysis of purple membrane-polyacrylamide film formation taking into account Fano line shapes and scattering.

    Science.gov (United States)

    Gomariz, María; Blaya, Salvador; Acebal, Pablo; Carretero, Luis

    2014-01-01

    We theoretically and experimentally analyze the formation of thick Purple Membrane (PM) polyacrylamide (PA) films by means of optical spectroscopy by considering the absorption of bacteriorhodopsin and scattering. We have applied semiclassical quantum mechanical techniques for the calculation of absorption spectra by taking into account the Fano effects on the ground state of bacteriorhodopsin. A model of the formation of PM-polyacrylamide films has been proposed based on the growth of polymeric chains around purple membrane. Experimentally, the temporal evolution of the polymerization process of acrylamide has been studied as function of the pH solution, obtaining a good correspondence to the proposed model. Thus, due to the formation of intermediate bacteriorhodopsin-doped nanogel, by controlling the polymerization process, an alternative methodology for the synthesis of bacteriorhodopsin-doped nanogels can be provided.

  20. Real-time UV-visible spectroscopy analysis of purple membrane-polyacrylamide film formation taking into account Fano line shapes and scattering.

    Directory of Open Access Journals (Sweden)

    María Gomariz

    Full Text Available We theoretically and experimentally analyze the formation of thick Purple Membrane (PM polyacrylamide (PA films by means of optical spectroscopy by considering the absorption of bacteriorhodopsin and scattering. We have applied semiclassical quantum mechanical techniques for the calculation of absorption spectra by taking into account the Fano effects on the ground state of bacteriorhodopsin. A model of the formation of PM-polyacrylamide films has been proposed based on the growth of polymeric chains around purple membrane. Experimentally, the temporal evolution of the polymerization process of acrylamide has been studied as function of the pH solution, obtaining a good correspondence to the proposed model. Thus, due to the formation of intermediate bacteriorhodopsin-doped nanogel, by controlling the polymerization process, an alternative methodology for the synthesis of bacteriorhodopsin-doped nanogels can be provided.

  1. Specific binding of activated Vip3Aa10 to Helicoverpa armigera brush border membrane vesicles results in pore formation.

    Science.gov (United States)

    Liu, Jing-Guo; Yang, Ai-Zhen; Shen, Xiao-Hong; Hua, Bao-Guang; Shi, Guang-Lu

    2011-10-01

    Helicoverpa armigera is one of the most harmful pests in China. Although it had been successfully controlled by Cry1A toxins, some H. armigera populations are building up resistance to Cry1A toxins in the laboratory. Vip3A, secreted by Bacillus thuringiensis, is another potential toxin against H. armigera. Previous reports showed that activated Vip3A performs its function by inserting into the midgut brush border membrane vesicles (BBMV) of susceptible insects. To further investigate the binding of Vip3A to BBMV of H. armigera, the full-length Vip3Aa10 toxin expressed in Escherichia coli was digested by trypsin or midgut juice extract, respectively. Among the fragments of digested Vip3Aa10, only a 62kDa fragment (Vip3Aa10-T) exhibited binding to BBMV of H. armigera and has insecticidal activity. Moreover, this interaction was specific and was not affected by the presence of Cry1Ab toxin. Binding of Vip3Aa10-T to BBMV resulted in the formation of an ion channel. Unlike Cry1A toxins, Vip3Aa10-T was just slightly associated with lipid rafts of BBMV. These data suggest that although activated Vip3Aa10 specifically interacts with BBMV of H. armigera and forms an ion channel, the mode of action of it may be different from that of Cry1A toxins.

  2. Solid supported membranes doped with PIP2: influence of ionic strength and pH on bilayer formation and membrane organization.

    Science.gov (United States)

    Braunger, Julia A; Kramer, Corinna; Morick, Daniela; Steinem, Claudia

    2013-11-19

    Phosphoinositides and in particular L-α-phosphatidylinositol-4,5-bisphosphate (PIP2) are key lipids controlling many cellular events and serve as receptors for a large number of intracellular proteins. To quantitatively analyze protein-PIP2 interactions in vitro in a time-resolved manner, planar membranes on solid substrates are highly desirable. Here, we describe an optimized protocol to form PIP2 containing planar solid supported membranes on silicon surfaces by vesicle spreading. Supported lipid bilayers (SLBs) were obtained by spreading POPC/PIP2 (92:8) small unilamellar vesicles onto hydrophilic silicon substrates at a low pH of 4.8. These membranes were capable of binding ezrin, resulting in large protein coverage as concluded from reflectometric interference spectroscopy and fluorescence microscopy. As deduced from fluorescence microscopy, only under low pH conditions, a homogeneously appearing distribution of fluorescently labeled PIP2 molecules in the membrane was achieved. Fluorescence recovery after photobleaching experiments revealed that PIP2 is not mobile in the bottom layer of the SLBs, while PIP2 is fully mobile in the top layer with diffusion coefficients of about 3 μm(2)/s. This diffusion coefficient was considerably reduced by a factor of about 3 if ezrin has been bound to PIP2 in the membrane.

  3. Characterization of Natural Organic Matter and Disinfection Byproducts Formation Potential in Pilot-Scale Coagulation-Ultrafiltration Membrane Combined Process in Winter

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yaozong; WANG Qishan; HE Fenghua; DING Shasha

    2010-01-01

    A pilot-scale ultrafiltration membrane plant was set up for treating Luanhe River water with flocculating and precipitation process of waterworks. The aim is to investigate the variation and characteristics of natural organic matter and disinfection byproducts formation potential in the whole process in winter. The results show that dissolved organic matter (DOM), UV254, trihaiomethanes formation potential (THMsFP) and haloacetic acids formation poten-tial (HAAsFP) of Luanhe River water were mainly distributed in the range of molecular weight (MW) <1 kDa, so were the membrane feed water and treated water by membrane. Specifc UV absorbance, specific THMsFP and spe-cific HAAsFP have the maximal value in the MW fraction of 1-3 kDa, except that specific UV absorbance of mem-brane feed water is in the range of 3-10 kDa; DOM of membrane backwash water is mainly distributed in the range of MW30 kDa and MW<1 kDa. It is the DOM in water backwashing in up way that made significant contribution to the higher dissolved organic carbon content in membrane backwash water. However, UV254, THMsFP and HAAsFP were mainly distributed in the range of MW<1 kDa. The highest concentrations of specific THMsFP and specific HAAsFP appeared in the MW fraction of 3-10 kDa. CHCl3 was the major THMs species during MBW chlorination and occupied more than 60% of the total THMsFP. Dichloroacetic acid and trichloroacetic acid were the main compo-nents in HAAsFP. The concentration of THMsFP and HAAsFP in MBW was influenced by operation period.

  4. Superficial dermal fibroblasts enhance basement membrane and epidermal barrier formation in tissue-engineered skin: implications for treatment of skin basement membrane disorders.

    Science.gov (United States)

    Varkey, Mathew; Ding, Jie; Tredget, Edward E

    2014-02-01

    Basement membrane is a highly specialized structure that binds the dermis and the epidermis of the skin, and is mainly composed of laminins, nidogen, collagen types IV and VII, and the proteoglycans, collagen type XVIII and perlecan, all of which play critical roles in the function and resilience of skin. Both dermal fibroblasts and epidermal keratinocytes contribute to the development of the basement membrane, and in turn the basement membrane and underlying dermis influence the development and function of the epidermal barrier. Disruption of the basement membrane results in skin fragility, extensive painful blistering, and severe recurring wounds as seen in skin basement membrane disorders such as epidermolysis bullosa, a family of life-threatening congenital skin disorders. Currently, there are no successful strategies for treatment of these disorders; we propose the use of tissue-engineered skin as a promising approach for effective wound coverage and to enhance healing. Fibroblasts and keratinocytes isolated from superficial and deep dermis and epidermis, respectively, of tissue from abdominoplasty patients were independently cocultured on collagen-glycosaminoglycan matrices, and the resulting tissue-engineered skin was assessed for functional differences based on the underlying specific dermal fibroblast subpopulation. Tissue-engineered skin with superficial fibroblasts and keratinocytes formed a continuous epidermis with increased epidermal barrier function and expressed higher levels of epidermal proteins, keratin-5, and E-cadherin, compared to that with deep fibroblasts and keratinocytes, which had an intermittent epidermis. Further, tissue-engineered skin with superficial fibroblasts and keratinocytes formed better basement membrane, and produced more laminin-5, nidogen, collagen type VII, compared to that with deep fibroblasts and keratinocytes. Overall, our results demonstrate that tissue-engineered skin with superficial fibroblasts and keratinocytes

  5. Listeriolysin O Membrane Damaging Activity Involves Arc Formation and Lineaction -- Implication for Listeria monocytogenes Escape from Phagocytic Vacuole.

    Directory of Open Access Journals (Sweden)

    Yi Ruan

    2016-04-01

    Full Text Available Listeriolysin-O (LLO plays a crucial role during infection by Listeria monocytogenes. It enables escape of bacteria from phagocytic vacuole, which is the basis for its spread to other cells and tissues. It is not clear how LLO acts at phagosomal membranes to allow bacterial escape. The mechanism of action of LLO remains poorly understood, probably due to unavailability of suitable experimental tools that could monitor LLO membrane disruptive activity in real time. Here, we used high-speed atomic force microscopy (HS-AFM featuring high spatio-temporal resolution on model membranes and optical microscopy on giant unilamellar vesicles (GUVs to investigate LLO activity. We analyze the assembly kinetics of toxin oligomers, the prepore-to-pore transition dynamics and the membrane disruption in real time. We reveal that LLO toxin efficiency and mode of action as a membrane-disrupting agent varies strongly depending on the membrane cholesterol concentration and the environmental pH. We discovered that LLO is able to form arc pores as well as damage lipid membranes as a lineactant, and this leads to large-scale membrane defects. These results altogether provide a mechanistic basis of how large-scale membrane disruption leads to release of Listeria from the phagocytic vacuole in the cellular context.

  6. Deletion of the glycosyltransferase bgsB of Enterococcus faecalis leads to a complete loss of glycolipids from the cell membrane and to impaired biofilm formation

    Directory of Open Access Journals (Sweden)

    Grohmann Elisabeth

    2011-04-01

    Full Text Available Abstract Background Deletion of the glycosyltransferase bgsA in Enterococcus faecalis leads to loss of diglucosyldiacylglycerol from the cell membrane and accumulation of its precursor monoglucosyldiacylglycerol, associated with impaired biofilm formation and reduced virulence in vivo. Here we analyzed the function of a putative glucosyltransferase EF2890 designated biofilm-associated glycolipid synthesis B (bgsB immediately downstream of bgsA. Results A deletion mutant was constructed by targeted mutagenesis in E. faecalis strain 12030. Analysis of cell membrane extracts revealed a complete loss of glycolipids from the cell membrane. Cell walls of 12030ΔbgsB contained approximately fourfold more LTA, and 1H-nuclear magnetic resonance (NMR spectroscopy suggested that the higher content of cellular LTA was due to increased length of the glycerol-phosphate polymer of LTA. 12030ΔbgsB was not altered in growth, cell morphology, or autolysis. However, attachment to Caco-2 cells was reduced to 50% of wild-type levels, and biofilm formation on polystyrene was highly impaired. Despite normal resistance to cationic antimicrobial peptides, complement and antibody-mediated opsonophagocytic killing in vitro, 12030ΔbgsB was cleared more rapidly from the bloodstream of mice than wild-type bacteria. Overall, the phenotype resembles the respective deletion mutant in the bgsA gene. Our findings suggest that loss of diglucosyldiacylglycerol or the altered structure of LTA in both mutants account for phenotypic changes observed. Conclusions In summary, BgsB is a glucosyltransferase that synthesizes monoglucosyldiacylglycerol. Its inactivation profoundly affects cell membrane composition and has secondary effects on LTA biosynthesis. Both cell-membrane amphiphiles are critical for biofilm formation and virulence of E. faecalis.

  7. Factors affecting the formation of zeolite seed layers and the effects of seed layers on the growth of zeolite silicalite-1 membranes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiongfu; LIU Hai'ou; WANG Anjie; WANG Jinqu

    2007-01-01

    The present study investigates the formation of silicalite-1 seed layers on a porous carbon support of 0.5 μm pore size and a-Al2O3 supports with different pore sizes (0.1 μm and 4 μm) via the slip-casting technique.The effects of support property,seed size and solvent on the formation of seed layers were investigated in detail.The growth of silicalite-1 membranes on different seeded supports by hydrothermal synthesis was also evaluated.The scanning electron microscopy (SEM) and X-ray diffraction (XRD) characterizations indicate that a continuous seed layer can be obtained on the smooth support of 0.1 μm pore size by using any seed of 100 nm,600 nm or 2.2 μm in size,whereas,on the coarse supports with either 0.5 μm or 4 μm pore size,a continuous seed layer cannot be formed using the above seed sizes and the same seeding time.At a longer contact time,a seed layer can also be formed using 100 nm seed on the supports with larger pore size.However,the layer is not uniform and smooth.For a hydrophobic porous carbon support,seeding ethanol suspension,which has weak polarity,favors the formation of a continuous seed layer.The seed layers and membranes grown from the smaller seed are more uniform and continuous and possess smoother surfaces than those from the larger seed.The seed layer and respective grown membrane formed from nanosized seed (100 nm) are the most uniform and compact.With this method of seeded secondary synthesis of zeolite membranes,the quality of a membrane mainly 、depends on the quality of the seed layer.

  8. Influence of Structure and Composition on Dynamic Viscoelastic Property of Cartilaginous Tissue: Criteria for Classification between Hyaline Cartilage and Fibrocartilage Based on Mechanical Function

    Science.gov (United States)

    Miyata, Shogo; Tateishi, Tetsuya; Furukawa, Katsuko; Ushida, Takashi

    Recently, many types of methodologies have been developed to regenerate articular cartilage. It is important to assess whether the reconstructed cartilaginous tissue has the appropriate mechanical functions to qualify as hyaline (articular) cartilage. In some cases, the reconstructed tissue may become fibrocartilage and not hyaline cartilage. In this study, we determined the dynamic viscoelastic properties of these two types of cartilage by using compression and shear tests, respectively. Hyaline cartilage specimens were harvested from the articular surface of bovine knee joints and fibrocartilage specimens were harvested from the meniscus tissue of the same. The results of this study revealed that the compressive energy dissipation of hyaline cartilage showed a strong dependence on testing frequency at low frequencies, while that of fibrocartilage did not. Therefore, the compressive energy dissipation that is indicated by the loss tangent could become the criterion for the in vitro assessment of the mechanical function of regenerated cartilage.

  9. Spontaneous hyaline cartilage regeneration can be induced in an osteochondral defect created in the femoral condyle using a novel double-network hydrogel

    National Research Council Canada - National Science Library

    Yokota, Masashi; Yasuda, Kazunori; Kitamura, Nobuto; Arakaki, Kazunobu; Onodera, Shin; Kurokawa, Takayuki; Gong, Jian-Ping

    2011-01-01

    .... The purpose is to clarify whether the spontaneous hyaline cartilage regeneration can be induced in a large osteochondral defect created in the femoral condyle by means of implanting a novel double-network (DN...

  10. Microstructural and compositional features of the fibrous and hyaline cartilage on the medial tibial plateau imply a unique role for the hopping locomotion of kangaroo

    National Research Council Canada - National Science Library

    He, Bo; Wu, Jian Ping; Xu, Jiake; Day, Robert E; Kirk, Thomas Brett

    2013-01-01

    .... However, the influences of the microstructure, composition and mechanical properties of the central fibrous and peripheral hyaline cartilage on the function of the knee joints are still to be defined...

  11. NSF- and SNARE-mediated membrane fusion is required for nuclear envelope formation and completion of nuclear pore complex assembly in Xenopus laevis egg extracts.

    Science.gov (United States)

    Baur, Tina; Ramadan, Kristijan; Schlundt, Andreas; Kartenbeck, Jürgen; Meyer, Hemmo H

    2007-08-15

    Despite the progress in understanding nuclear envelope (NE) reformation after mitosis, it has remained unclear what drives the required membrane fusion and how exactly this is coordinated with nuclear pore complex (NPC) assembly. Here, we show that, like other intracellular fusion reactions, NE fusion in Xenopus laevis egg extracts is mediated by SNARE proteins that require activation by NSF. Antibodies against Xenopus NSF, depletion of NSF or the dominant-negative NSF(E329Q) variant specifically inhibited NE formation. Staging experiments further revealed that NSF was required until sealing of the envelope was completed. Moreover, excess exogenous alpha-SNAP that blocks SNARE function prevented membrane fusion and caused accumulation of non-flattened vesicles on the chromatin surface. Under these conditions, the nucleoporins Nup107 and gp210 were fully recruited, whereas assembly of FxFG-repeat-containing nucleoporins was blocked. Together, we define NSF- and SNARE-mediated membrane fusion events as essential steps during NE formation downstream of Nup107 recruitment, and upstream of membrane flattening and completion of NPC assembly.

  12. Formats

    Directory of Open Access Journals (Sweden)

    Gehmann, Ulrich

    2012-03-01

    Full Text Available In the following, a new conceptual framework for investigating nowadays’ “technical” phenomena shall be introduced, that of formats. The thesis is that processes of formatting account for our recent conditions of life, and will do so in the very next future. It are processes whose foundations have been laid in modernity and which will further unfold for the time being. These processes are embedded in the format of the value chain, a circumstance making them resilient to change. In addition, they are resilient in themselves since forming interconnected systems of reciprocal causal circuits.Which leads to an overall situation that our entire “Lebenswelt” became formatted to an extent we don’t fully realize, even influencing our very percep-tion of it.

  13. The classical and alternative pathways of complement activation play distinct roles in spontaneous C3 fragment deposition and membrane attack complex (MAC) formation on human B lymphocytes

    DEFF Research Database (Denmark)

    Leslie, Robert Graham Quinton; Nielsen, Claus Henrik

    2004-01-01

    The contributions of the classical (CP) and alternative (AP) pathways of complement activation to the spontaneous deposition of C3 fragments and the formation of membrane attack complexes (MAC) on human B lymphocytes, were assessed by incubating peripheral blood mononuclear cells with autologous ...... of MAC formation was also found to be highly pathway dependent, with the AP being about 15-fold more efficient at initiating this process than the CP. A model accounting for the effectiveness of the AP in both preserving C3 fragment integrity and initiating MAC is presented....

  14. Formation of Gel-like Nanodomains in Cholesterol-Containing Sphingomyelin or Phosphatidylcholine Binary Membrane As Examined by Fluorescence Lifetimes and (2)H NMR Spectra.

    Science.gov (United States)

    Yasuda, Tomokazu; Matsumori, Nobuaki; Tsuchikawa, Hiroshi; Lönnfors, Max; Nyholm, Thomas K M; Slotte, J Peter; Murata, Michio

    2015-12-29

    In this study, we measured the time-resolved fluorescence of trans-parinaric acid (tPA), steady-state fluorescence anisotropy of diphenylhexatriene (DPH), and (2)H NMR of 10,10-d2-stearoyl lipids in stearoyl sphingomyelin with cholesterol (SSM/Chol) and l-palmitoyl-2-stearoyl-sn-glycero-3-phosphocholine with Chol (PSPC/Chol) binary membranes. The results suggest that the membrane order obtained from the fluorescence experiments shows a similar temperature dependency as those of the (2)H NMR data. More importantly, the time-resolved fluorescence data implied the presence of at least two types of domains, cholesterol-poor gel-like domains (CPGLD) and cholesterol-enriched liquid-ordered (Lo) domains. These domains appear on a nano-to-micro second time scale for both SSM-Chol and PSPC-Chol membranes. The relative size of the gel-like domain was also estimated from the temperature-dependent lifetime measurements and (2)H NMR spectral changes. The results imply that the size of the gel-like domains is very small, probably on the nanometer scale, and smaller in SSM-Chol membrane than those in PSPC-Chol bilayers, which could account for the higher thermal stability of SM-Chol membranes. The present study demonstrates that gel-like nanodomains occur in SM-Chol binary membrane even with Chol content of over 33 mol %, which has been thought to consist exclusively of Lo phase, implying that not only Lo domains but also gel-like nanodomains are important for formation of lipid-ordered phase in SM-Chol and PC-Chol membranes.

  15. Hyaline cartilage regeneration by combined therapy of microfracture and long-term bone morphogenetic protein-2 delivery.

    Science.gov (United States)

    Yang, Hee Seok; La, Wan-Geun; Bhang, Suk Ho; Kim, Hak-Jun; Im, Gun-Il; Lee, Haeshin; Park, Jung-Ho; Kim, Byung-Soo

    2011-07-01

    Microfracture of cartilage induces migration of bone-marrow-derived mesenchymal stem cells. However, this treatment often results in fibrocartilage regeneration. Growth factors such as bone morphogenetic protein (BMP)-2 induce the differentiation of bone-marrow-derived mesenchymal stem cells into chondrocytes, which can be used for hyaline cartilage regeneration. Here, we tested the hypothesis that long-term delivery of BMP-2 to cartilage defects subjected to microfracture results in regeneration of high-quality hyaline-like cartilage, as opposed to short-term delivery of BMP-2 or no BMP-2 delivery. Heparin-conjugated fibrin (HCF) and normal fibrin were used as carriers for the long- and short-term delivery of BMP-2, respectively. Rabbit articular cartilage defects were treated with microfracture combined with one of the following: no treatment, fibrin, short-term delivery of BMP-2, HCF, or long-term delivery of BMP-2. Eight weeks after treatment, histological analysis revealed that the long-term delivery of BMP-2 group (microfracture + HCF + BMP-2) showed the most staining with alcian blue. A biochemical assay, real-time polymerase chain reaction assay and Western blot analysis all revealed that the long-term delivery of BMP-2 group had the highest glucosaminoglycan content as well as the highest expression level of collagen type II. Taken together, the long-term delivery of BMP-2 to cartilage defects subjected to microfracture resulted in regeneration of hyaline-like cartilage, as opposed to short-term delivery or no BMP-2 delivery. Therefore, this method could be more convenient for hyaline cartilage regeneration than autologous chondrocyte implantation due to its less invasive nature and lack of cell implantation.

  16. Inorganic Fe2+ formation upon Fe-S protein thermodestruction in the membranes of thermophilic cyanobacteria: Mössbauer spectroscopy study.

    Science.gov (United States)

    Kaurov YuN; Novakova, A A; Davletshina, L N; Aleksandrov AYu; Khval'kovskaya, E A; Semin, B K; Belevich, N P; Ivanov, I I; Rubin, A B

    1999-04-30

    A model description of the Mössbauer spectrum (80 K) of native membranes of the thermophilic cyanobacterium Synechococcus elongatus is suggested on the basis of the known values of quadrupole splitting (deltaE(Q)) and isomer shift (deltaFe) for the iron-containing components of the photosynthetic apparatus. Using this approach, we found that heating the membranes at 70-80 K results in a decrease of doublet amplitudes belonging to F(X), F(A), F(B) and ferredoxin and simultaneous formation of a new doublet with deltaE(Q) = 3.10 mm/s and delta-Fe = 1.28 mm/s, typical of inorganic hydrated forms of Fe2+. The inhibition of electron transfer via photosystem I to oxygen, catalyzed by ferredoxin, occurs within the same range of temperatures. The data demonstrate that the processes of thermoinduced Fe2+ formation and distortions in the photosystem I electron transport in the membranes are interrelated and caused mainly by the degradation of ferredoxin. The possible role of Fe2+ formation in the damage of the photosynthetic apparatus resulting from heating and the action of other extreme factors is discussed.

  17. Rotating three-dimensional dynamic culture of adult human bone marrow-derived cells for tissue engineering of hyaline cartilage.

    Science.gov (United States)

    Sakai, Shinsuke; Mishima, Hajime; Ishii, Tomoo; Akaogi, Hiroshi; Yoshioka, Tomokazu; Ohyabu, Yoshimi; Chang, Fei; Ochiai, Naoyuki; Uemura, Toshimasa

    2009-04-01

    The method of constructing cartilage tissue from bone marrow-derived cells in vitro is considered a valuable technique for hyaline cartilage regenerative medicine. Using a rotating wall vessel (RWV) bioreactor developed in a NASA space experiment, we attempted to efficiently construct hyaline cartilage tissue from human bone marrow-derived cells without using a scaffold. Bone marrow aspirates were obtained from the iliac crest of nine patients during orthopedic operation. After their proliferation in monolayer culture, the adherent cells were cultured in the RWV bioreactor with chondrogenic medium for 2 weeks. Cells from the same source were cultured in pellet culture as controls. Histological and immunohistological evaluations (collagen type I and II) and quantification of glycosaminoglycan were performed on formed tissues and compared. The engineered constructs obtained using the RWV bioreactor showed strong features of hyaline cartilage in terms of their morphology as determined by histological and immunohistological evaluations. The glycosaminoglycan contents per microg DNA of the tissues were 10.01 +/- 3.49 microg/microg DNA in the case of the RWV bioreactor and 6.27 +/- 3.41 microg/microg DNA in the case of the pellet culture, and their difference was significant. The RWV bioreactor could provide an excellent environment for three-dimensional cartilage tissue architecture that can promote the chondrogenic differentiation of adult human bone marrow-derived cells.

  18. Regeneration of hyaline cartilage by cell-mediated gene therapy using transforming growth factor beta 1-producing fibroblasts.

    Science.gov (United States)

    Lee, K H; Song, S U; Hwang, T S; Yi, Y; Oh, I S; Lee, J Y; Choi, K B; Choi, M S; Kim, S J

    2001-09-20

    Transforming growth factor beta (TGF-beta) has been considered as a candidate for gene therapy of orthopedic diseases. The possible application of cell-mediated TGF-beta gene therapy as a new treatment regimen for degenerative arthritis was investigated. In this study, fibroblasts expressing active TGF-beta 1 were injected into the knee joints of rabbits with artificially made cartilage defects to evaluate the feasibility of this therapy for orthopedic diseases. Two to 3 weeks after the injection there was evidence of cartilage regeneration, and at 4 to 6 weeks the cartilage defect was completely filled with newly grown hyaline cartilage. Histological analyses of the regenerated cartilage suggested that it was well integrated with the adjacent normal cartilage at the sides of the defect and that the newly formed tissue was indeed hyaline cartilage. Our findings suggest that cell-mediated TGF-beta 1 gene therapy may be a novel treatment for orthopedic diseases in which hyaline cartilage damage has occurred.

  19. Effects of growth factors and glucosamine on porcine mandibular condylar cartilage cells and hyaline cartilage cells for tissue engineering applications.

    Science.gov (United States)

    Wang, Limin; Detamore, Michael S

    2009-01-01

    Temporomandibular joint (TMJ) condylar cartilage is a distinct cartilage that has both fibrocartilaginous and hyaline-like character, with a thin proliferative zone that separates the fibrocartilaginous fibrous zone at the surface from the hyaline-like mature and hypertrophic zones below. In this study, we compared the effects of insulin-like growth factor-I (IGF-I), basic fibroblast growth factor (bFGF), transforming growth factor beta1 (TGF-beta1), and glucosamine sulphate on porcine TMJ condylar cartilage and ankle cartilage cells in monolayer culture. In general, TMJ condylar cartilage cells proliferated faster than ankle cartilage cells, while ankle cells produced significantly greater amounts of glycosaminoglycans (GAGs) and collagen than TMJ condylar cartilage cells. IGF-I and bFGF were potent stimulators of TMJ cell proliferation, while no signals statistically outperformed controls for ankle cell proliferation. IGF-I was the most effective signal for GAG production with ankle cells, and the most potent upregulator of collagen synthesis for both cell types. Glucosamine sulphate promoted cell proliferation and biosynthesis at specific concentrations and outperformed growth factors in certain instances. In conclusion, hyaline cartilage cells had lower cell numbers and superior biosynthesis compared to TMJ condylar cartilage cells, and we have found IGF-I at 100 ng/mL and glucosamine sulphate at 100 microg/mL to be the most effective signals for these cells under the prescribed conditions.

  20. Capsid protein VP4 of human rhinovirus induces membrane permeability by the formation of a size-selective multimeric pore.

    Directory of Open Access Journals (Sweden)

    Anusha Panjwani

    2014-08-01

    Full Text Available Non-enveloped viruses must deliver their viral genome across a cell membrane without the advantage of membrane fusion. The mechanisms used to achieve this remain poorly understood. Human rhinovirus, a frequent cause of the common cold, is a non-enveloped virus of the picornavirus family, which includes other significant pathogens such as poliovirus and foot-and-mouth disease virus. During picornavirus cell entry, the small myristoylated capsid protein VP4 is released from the virus, interacts with the cell membrane and is implicated in the delivery of the viral RNA genome into the cytoplasm to initiate replication. In this study, we have produced recombinant C-terminal histidine-tagged human rhinovirus VP4 and shown it can induce membrane permeability in liposome model membranes. Dextran size-exclusion studies, chemical crosslinking and electron microscopy demonstrated that VP4 forms a multimeric membrane pore, with a channel size consistent with transfer of the single-stranded RNA genome. The membrane permeability induced by recombinant VP4 was influenced by pH and was comparable to permeability induced by infectious virions. These findings present a molecular mechanism for the involvement of VP4 in cell entry and provide a model system which will facilitate exploration of VP4 as a novel antiviral target for the picornavirus family.

  1. Castleman′s disease - hyaline vascular type - clinical, cytological and histological features with review of literature

    Directory of Open Access Journals (Sweden)

    Ghosh Arnab

    2010-04-01

    Full Text Available Background and Aims: Castleman′s disease (CD is a rare disease of lymph node with two identified forms - the hyaline vascular (HV type or angiofollicular type and plasma cell (PC type. It usually presents as localized or systemic lymphadenopathy or even as extra nodal mass and may give rise to several differential diagnoses. Fine needle aspiration cytology (FNAC, as the initial investigation, may be misleading. Excision biopsy usually gives the diagnosis. This study analyzes the clinical, cytological and histological features of CD of HV type Materials and Methods: All the cases of CD reported between 2001 and March 2008 have been reviewed. Cytology and histopathology slides of all cases were reviewed by two reporting pathologists independently and the clinical records were analyzed. Result: We had five cases of CD all of which presented as cervical lymphadenopathy of 1 to 5 cms in young patients. Patients were mostly asymptomatic with all relevant investigations within normal limits. The cytology findings mostly showed a predominance of small lymphocytes with capillary fragments. On excision biopsy, all cases were diagnosed as CD of HV type. Conclusion: CD should be kept as a differential of lymphadenopathy, especially in asymptomatic and young patients.

  2. Absence of hyaline cartilage in the tongue of 'Caspian miniature horse'.

    Science.gov (United States)

    Rezaian, M

    2006-08-01

    Histology of the tongue, including apex, root and body, in four adult Caspian miniature horses was examined. Serial sections with 6 mum thickness were stained with haematoxylin-eosin and Masson trichrome and studied under light microscope. The tongue was covered by stratified squamous epithelium. It was thick and keratinized bearing numerous lingual papillae on the dorsum, mostly filiform with a very fine keratinized thread projecting above the surface and bending backward. The fungiform papillae were sparsely scattered among the filiform papillae and covered with keratinized squamous epithelium. Few taste buds were detected on it. The two very large vallate papillae were detected on the dorsum, just rostral to the root, which were covered with stratified squamous epithelium with relatively high amounts of taste buds in the epithelium of the surrounding grooves. The foliate papillae were present near the palatoglossal arch and had a few taste buds. The epithelium covering the ventral surface of the tongue was thin and keratinized. The lingual muscle core consisted of transverse, longitudinal and perpendicular bundles of skeletal muscle fibres. Clusters of minor salivary glands were present between the muscle fibres and lamia propria. Most of the lingual glands were mucous and most of the gustatory ones were serous type. The mid-dorsal special structure of the tongue (dorsal lingual cartilage) contained sparse skeletal muscle fibres and was rich in white adipose tissue. Hyaline cartilage, routinely observed in this structure in the horses, was not detected in Caspian miniature horse.

  3. [Quantitative analysis of chondrocyte distribution patterns in hyaline cartilage tissue--a comparison of different models].

    Science.gov (United States)

    Ranke, T P; Ranke, I; Schwandtke, A; Rother, P

    1989-01-01

    The purpose of our investigations were aging changes in hyaline cartilage of the trachea and of the larynx. 42 samples of carina tracheae and 29 samples of arytenoid cartilage were used in both organs from the newborn age up to the age of 91 a. We have examined patterns of cell distribution with the help of the computer programme "Dichte" ("density") using the following methods of stochastic geometry: product density, L function, and others. Product density allows for a reliable destination between a regular pattern of cells (hard-core distribution), a random pattern (soft-core distribution), and a typical clustering of chondrocytes. 2 examples of arytenoid cartilage have been selected to demonstrate the possibilities of interpretation of product density supported by the L function. Soft-core and in few cases hard-core distribution have been found both with the carina tracheae and the cartilago arytaenoidea in the 1st decade of life. Beginning with the 2nd decade of life, the typical clustering of chondrocytes have been confirmed with both organs.

  4. Complex formation between primycin and ergosterol: entropy-driven initiation of modification of the fungal plasma membrane structure

    National Research Council Canada - National Science Library

    Virág, Eszter; Pesti, Miklós; Kunsági-Máté, Sándor

    2012-01-01

    The interaction of the antibiotic primycin with the main fungal sterol, ergosterol, was investigated in vitro in order to monitor the effect of primycin on the fungal plasma membrane at the molecular level...

  5. MORPHOGENESIS OF KNEE HYALINE CARTILAGE DURING INTRAARTICULAR INJECTION OF PLATELET-RICH AUTOLOGOUS PLASMA AND/OR HYALURONIC ACID PREPARATION IN RATS WITH EXPERIMENTAL OSTEOARTHRITIS

    Directory of Open Access Journals (Sweden)

    S. A. Demkin

    2016-01-01

    Full Text Available According to current concepts, the influence of autologous platelet-rich plasma (PRP and high molecular hyaluronates (HA on the repair of hyaline cartilage during its inflammatory and degenerative changes has been insufficiently studied yet. The objective of the work was to evaluate the morphological changes in the structure of hyaline cartilage in experimental osteoarthritis after intra-articular injection of PRP and/or HA. Material and methods. The authors used 50 adult rats of Wistar line, weighing 250±2,2 g., distributed into five groups of 10 animals (two control and three experimental groups. An experimental gonarthosis was simulated on four groups of animals. Animals of the first experimental group received intra-articular injection of PRP, the second group – HA, the third – both PRP and HA. Results. No morphological signs of degenerative and inflammatory changes in the first control group were identified. Following osteoarthritis simulation the articular cartilage thinned to 121±20,4 microns (p<0,05 and the volume fraction of chondrocyte decreased to 1,2±0,6% (p<0,05. The authors observed an uneven coloration of collagen fibers with severe tinctorial properties disorder of the articular cartilage matrix. After the RPR introduction the authors observed tickening of the articular cartilage up to 275±18,9 micron (p<0,05 and the volume fraction of chondrocytes up to 18,4±2,0% (p<0,05. The contour of the cartilage surface became smoother with the formation of a cell-free zone. Collagen fibers demonstrated a uniform distribution, tinctorial properties of cartilage matrix in all areas were preserved, no signs of inflammation were noted. After HA introduction the authors observed thickening of the cartilage plate up to 264±21,3 microns (p<0,05 and the volume fraction of chondrocytes up to 11,6±1,2% (p<0,05. The surface of the cartilage featured uneven contours due to multiple areas of pulping. Uneven tinctorial properties of cartilage

  6. Identification of an Atypical Membrane Protein Involved in the Formation of Protein Disulfide Bonds in Oxygenic Photosynthetic Organisms*S⃞

    OpenAIRE

    Singh, Abhay K.; Bhattacharyya-Pakrasi, Maitrayee; Pakrasi, Himadri B.

    2008-01-01

    The evolution of oxygenic photosynthesis in cyanobacteria nearly three billion years ago provided abundant reducing power and facilitated the elaboration of numerous oxygen-dependent reactions in our biosphere. Cyanobacteria contain an internal thylakoid membrane system, the site of photosynthesis, and a typical Gram-negative envelope membrane system. Like other organisms, the extracytoplasmic space in cyanobacteria houses numerous cysteine-containing proteins. However, the ...

  7. Effect of in-situ application of ultrasonic waves during formation of silver nanoparticles embedded in phospholipid membrane

    Science.gov (United States)

    Kim, Yongdeok; Hwan An, Hyeun; Bae Han, Won; Kim, Hee-Soo; Jun Kim, Suk; Seung Yoon, Chong

    2013-10-01

    Effect of in-situ application of ultrasonic waves (up to 1 MHz) on the Ag nanoparticles spontaneously produced inside the 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) membrane by thermal evaporation of Ag was studied by placing the membrane on a ultrasonic transducer during the metal deposition. Application of the ultrasonic vibration promoted spatial ordering of the deposited nanoparticles due to the induced phase transition from Lα to HII for DOPE. Arising from the agitation effect, particle size refinement, which depended on the amplitude of the ultrasonic vibration, was observed. It was also shown that a stiff gel state 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) membrane can be made locally permeable to incident Ag atoms by introducing DOPE molecules into the DPPC membrane as the Ag nanoparticles preferentially nucleated in the DOPE-rich region. Application of ultrasonic vibration with increasingly higher amplitude or frequency made the Ag nanoparticles uniformly distributed in the DPPC, suggesting that the permeability of the DPPC membrane can be temporarily increased without permanently damaging the membrane by addition of liquid crystalline lipids and subsequent application of ultrasonic waves.

  8. Combined Effects of Curcumin and (-)-Epigallocatechin Gallate on Inhibition of N-Acylhomoserine Lactone-Mediated Biofilm Formation in Wastewater Bacteria from Membrane Bioreactor.

    Science.gov (United States)

    Lade, Harshad; Paul, Diby; Kweon, Ji Hyang

    2015-11-01

    This work investigated the potential of curcumin (CCM) and (-)-epigallocatechin gallate (EGCG) to inhibit N-acyl homoserine lactone (AHL)-mediated biofilm formation in gramnegative bacteria from membrane bioreactor (MBR) activated sludge. The minimum inhibitory concentrations (MICs) of CCM alone against all the tested bacteria were 200-350 μg/ml, whereas those for EGCG were 300-600 μg/ml. Biofilm formation at one-half MICs indicated that CCM and EGCG alone respectively inhibited 52-68% and 59-78% of biofilm formation among all the tested bacteria. However, their combination resulted in 95-99% of biofilm reduction. Quorum sensing inhibition (QSI) assay with known biosensor strains demonstrated that CCM inhibited the expression of C4 and C6 homoserine lactones (HSLs)-mediated phenotypes, whereas EGCG inhibited C4, C6, and C10 HSLs-based phenotypes. The Center for Disease Control biofilm reactor containing a multispecies culture of nine bacteria with onehalf MIC of CCM (150 μg/ml) and EGCG (275 μg/ml) showed 17 and 14 μg/cm(2) of extracellular polymeric substances (EPS) on polyvinylidene fluoride membrane surface, whereas their combination (100 μg/ml of each) exhibited much lower EPS content (3 μg/cm(2)). Confocal laser scanning microscopy observations also illustrated that the combination of compounds tremendously reduced the biofilm thickness. The combined effect of CCM with EGCG clearly reveals for the first time the enhanced inhibition of AHL-mediated biofilm formation in bacteria from activated sludge. Thus, such combined natural QSI approach could be used for the inhibition of membrane biofouling in MBRs treating wastewaters.

  9. Effect of temperature on the formation and inactivation of syringomycin E pores in human red blood cells and bimolecular lipid membranes.

    Science.gov (United States)

    Agner, G; Kaulin, Y A; Schagina, L V; Takemoto, J Y; Blasko, K

    2000-06-01

    The effects of temperature on the formation and inactivation of syringomycin E (SRE) pores were investigated with human red blood cells (RBCs) and lipid bilayer membranes (BLMs). SRE enhanced the RBC membrane permeability of 86Rb and monomeric hemoglobin in a temperature dependent manner. The kinetics of 86Rb and hemoglobin effluxes were measured at different temperatures and pore formation was found to be only slightly affected, while inactivation was strongly influenced by temperature. At 37 degrees C, SRE pore inactivation began 15 min after and at 20 degrees C, 40 min after SRE addition. At 6 degrees C, below the phase transition temperature of the major lipid components of the RBC membrane, no inactivation occurred for as long as 90 min. With BLMs, SRE induced a large current that remained stable at 14 degrees C, but at 23 degrees C it decreased over time while the single channel conductance and dwell time did not change. The results show that the temperature dependent inactivation of SRE pores is due to a decrease in the number of open pores.

  10. Deleted in Malignant Brain Tumors 1 (DMBT1) is present in hyaline membranes and modulates surface tension of surfactant

    DEFF Research Database (Denmark)

    Müller, Hanna; End, Caroline; Renner, Marcus

    2007-01-01

    BACKGROUND: Deleted in Malignant Brain Tumors 1 (DMBT1) is a secreted scavenger receptor cysteine-rich protein that binds various bacteria and is thought to participate in innate pulmonary host defense. We hypothesized that pulmonary DMBT1 could contribute to respiratory distress syndrome in neon...

  11. Drug-induced hemolytic anemia and thrombocytopenia associated with alterations of cell membrane lipids and acanthocyte formation.

    Science.gov (United States)

    Poulet, Frederique M; Penraat, Kelley; Collins, Nathaniel; Evans, Ellen; Thackaberry, Evan; Manfra, Denise; Engstrom, Laura; Geissler, Richard; Geraci-Erck, Maria; Frugone, Carlos; Abutarif, Malaz; Fine, Jay S; Peterson, Brianna L; Cummings, Brian S; Johnson, Robert C

    2010-10-01

    CXCR3 is a chemokine receptor, upregulated upon activation of T cells and expressed on nearly 100% of T cells in sites of inflammation. SCH 900875 is a selective CXCR3 receptor antagonist. Thrombocytopenia and severe hemolytic anemia with acanthocytosis occurred in rats at doses of 75, 100, and 150 mg/kg/day. Massively enlarged spleens corresponded histologically to extramedullary hematopoiesis, macrophages, and hemosiderin pigment and sinus congestion. Phagocytosed erythrocytes and platelets were within splenic macrophages. IgG and/or IgM were not detected on erythrocyte and platelet membranes. Ex vivo increased osmotic fragility of RBCs was observed. Lipid analysis of the RBC membrane revealed modifications in phosphatidylcholine, overall cholesterol, and/or sphingomyelin. Platelets exhibited slender filiform processes on their plasma membranes, analogous to those of acanthocytes. The presence of similar morphological abnormalities in acanthocytes and platelets suggests that possibly similar alterations in the lipid composition of the plasma membrane have taken place in both cell types. This phenotype correlated with alterations in plasma lipids (hypercholesterolemia and low triglycerides) that occurred after SCH 900875 administration, although other factors cannot be excluded. The increased cell destruction was considered triggered by alterations in the lipid profile of the plasma membranes of erythrocytes and platelets, as reflected morphologically.

  12. Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) of cadaveric shoulders: comparison of contrast dynamics in hyaline and fibrous cartilage after intraarticular gadolinium injection.

    Science.gov (United States)

    Wiener, E; Hodler, J; Pfirrmann, C W A

    2009-01-01

    Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) is a novel method to investigate cartilaginous and fibrocartilaginous structures. To investigate the contrast dynamics in hyaline and fibrous cartilage of the glenohumeral joint after intraarticular injection of gadopentetate dimeglumine. Transverse T(1) maps were acquired on a 1.5T scanner before and after intraarticular injection of 2.0 mmol/l gadopentetate dimeglumine in five cadaveric shoulders using a dual flip angle three-dimensional gradient echo (3D-GRE) sequence. The acquisition time for the T(1) maps was 5 min 5 s for the whole shoulder. Measurements were repeated every 15 min over 2.5 hours. Regions of interest (ROIs) covering the glenoid cartilage and the labrum were drawn to assess the temporal evolution of the relaxation parameters. T(1) of unenhanced hyaline cartilage of the glenoid was 568+/-34 ms. T(1) of unenhanced fibrous cartilage of the labrum was 552+/-38 ms. Significant differences (P=0.002 and 0.03) in the relaxation parameters were already measurable after 15 min. After 2 to 2.5 hours, hyaline and fibrous cartilage still demonstrated decreasing relaxation parameters, with a larger range of the T(1)(Gd) values in fibrous cartilage. T(1) and triangle Delta R(1) values of hyaline and fibrous cartilage after 2.5 hours were 351+/-16 ms and 1.1+/-0.09 s(-1), and 332+/-31 ms and 1.2+/-0.1 s(-1), respectively. A significant decrease in T(1)(Gd) was found 15 min after intraarticular contrast injection. Contrast accumulation was faster in hyaline than in fibrous cartilage. After 2.5 hours, contrast accumulation showed a higher rate of decrease in hyaline cartilage, but neither hyaline nor fibrous cartilage had reached equilibrium.

  13. Delayed Gadolinium-Enhanced MRI of Cartilage (dGEMRIC) of Cadaveric Shoulders: Comparison of Contrast Dynamics in Hyaline and Fibrous Cartilage after Intraarticular Gadolinium Injection

    Energy Technology Data Exchange (ETDEWEB)

    Wiener, E. (Dept. of Radiology, Charite Universitaetsmedizin Berlin (Germany)); Hodler, J.; Pfirrmann, C.W.A. (Dept. of Radiology, Orthopedic Univ. Hospital Balgrist, Zuerich (Switzerland))

    2009-01-15

    Background: Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) is a novel method to investigate cartilaginous and fibrocartilaginous structures. Purpose: To investigate the contrast dynamics in hyaline and fibrous cartilage of the glenohumeral joint after intraarticular injection of gadopentetate dimeglumine. Material and Methods: Transverse T1 maps were acquired on a 1.5T scanner before and after intraarticular injection of 2.0 mmol/l gadopentetate dimeglumine in five cadaveric shoulders using a dual flip angle three-dimensional gradient echo (3D-GRE) sequence. The acquisition time for the T1 maps was 5 min 5 s for the whole shoulder. Measurements were repeated every 15 min over 2.5 hours. Regions of interest (ROIs) covering the glenoid cartilage and the labrum were drawn to assess the temporal evolution of the relaxation parameters. Results: T1 of unenhanced hyaline cartilage of the glenoid was 568+-34 ms. T1 of unenhanced fibrous cartilage of the labrum was 552+-38 ms. Significant differences (P=0.002 and 0.03) in the relaxation parameters were already measurable after 15 min. After 2 to 2.5 hours, hyaline and fibrous cartilage still demonstrated decreasing relaxation parameters, with a larger range of the T1(Gd) values in fibrous cartilage. T1 and ?R1 values of hyaline and fibrous cartilage after 2.5 hours were 351+-16 ms and 1.1+-0.09/s, and 332+-31 ms and 1.2+-0.1/s, respectively. Conclusion: A significant decrease in T1(Gd) was found 15 min after intraarticular contrast injection. Contrast accumulation was faster in hyaline than in fibrous cartilage. After 2.5 hours, contrast accumulation showed a higher rate of decrease in hyaline cartilage, but neither hyaline nor fibrous cartilage had reached equilibrium

  14. Microstructural and compositional features of the fibrous and hyaline cartilage on the medial tibial plateau imply a unique role for the hopping locomotion of kangaroo.

    Directory of Open Access Journals (Sweden)

    Bo He

    Full Text Available Hopping provides efficient and energy saving locomotion for kangaroos, but it results in great forces in the knee joints. A previous study has suggested that a unique fibrous cartilage in the central region of the tibial cartilage could serve to decrease the peak stresses generated within kangaroo tibiofemoral joints. However, the influences of the microstructure, composition and mechanical properties of the central fibrous and peripheral hyaline cartilage on the function of the knee joints are still to be defined. The present study showed that the fibrous cartilage was thicker and had a lower chondrocyte density than the hyaline cartilage. Despite having a higher PG content in the middle and deep zones, the fibrous cartilage had an inferior compressive strength compared to the peripheral hyaline cartilage. The fibrous cartilage had a complex three dimensional collagen meshwork with collagen bundles parallel to the surface in the superficial zone, and with collagen bundles both parallel and perpendicular to the surface in the middle and deep zones. The collagen in the hyaline cartilage displayed a typical Benninghoff structure, with collagen fibres parallel to the surface in the superficial zone and collagen fibres perpendicular to the surface in the deep zone. Elastin fibres were found throughout the entire tissue depth of the fibrous cartilage and displayed a similar alignment to the adjacent collagen bundles. In comparison, the elastin fibres in the hyaline cartilage were confined within the superficial zone. This study examined for the first time the fibrillary structure, PG content and compressive properties of the central fibrous cartilage pad and peripheral hyaline cartilage within the kangaroo medial tibial plateau. It provided insights into the microstructure and composition of the fibrous and peripheral hyaline cartilage in relation to the unique mechanical properties of the tissues to provide for the normal activities of kangaroos.

  15. Microstructural and compositional features of the fibrous and hyaline cartilage on the medial tibial plateau imply a unique role for the hopping locomotion of kangaroo.

    Science.gov (United States)

    He, Bo; Wu, Jian Ping; Xu, Jiake; Day, Robert E; Kirk, Thomas Brett

    2013-01-01

    Hopping provides efficient and energy saving locomotion for kangaroos, but it results in great forces in the knee joints. A previous study has suggested that a unique fibrous cartilage in the central region of the tibial cartilage could serve to decrease the peak stresses generated within kangaroo tibiofemoral joints. However, the influences of the microstructure, composition and mechanical properties of the central fibrous and peripheral hyaline cartilage on the function of the knee joints are still to be defined. The present study showed that the fibrous cartilage was thicker and had a lower chondrocyte density than the hyaline cartilage. Despite having a higher PG content in the middle and deep zones, the fibrous cartilage had an inferior compressive strength compared to the peripheral hyaline cartilage. The fibrous cartilage had a complex three dimensional collagen meshwork with collagen bundles parallel to the surface in the superficial zone, and with collagen bundles both parallel and perpendicular to the surface in the middle and deep zones. The collagen in the hyaline cartilage displayed a typical Benninghoff structure, with collagen fibres parallel to the surface in the superficial zone and collagen fibres perpendicular to the surface in the deep zone. Elastin fibres were found throughout the entire tissue depth of the fibrous cartilage and displayed a similar alignment to the adjacent collagen bundles. In comparison, the elastin fibres in the hyaline cartilage were confined within the superficial zone. This study examined for the first time the fibrillary structure, PG content and compressive properties of the central fibrous cartilage pad and peripheral hyaline cartilage within the kangaroo medial tibial plateau. It provided insights into the microstructure and composition of the fibrous and peripheral hyaline cartilage in relation to the unique mechanical properties of the tissues to provide for the normal activities of kangaroos.

  16. Engineering of hyaline cartilage with a calcified zone using bone marrow stromal cells.

    Science.gov (United States)

    Lee, W D; Hurtig, M B; Pilliar, R M; Stanford, W L; Kandel, R A

    2015-08-01

    In healthy joints, a zone of calcified cartilage (ZCC) provides the mechanical integration between articular cartilage and subchondral bone. Recapitulation of this architectural feature should serve to resist the constant shear force from the movement of the joint and prevent the delamination of tissue-engineered cartilage. Previous approaches to create the ZCC at the cartilage-substrate interface have relied on strategic use of exogenous scaffolds and adhesives, which are susceptible to failure by degradation and wear. In contrast, we report a successful scaffold-free engineering of ZCC to integrate tissue-engineered cartilage and a porous biodegradable bone substitute, using sheep bone marrow stromal cells (BMSCs) as the cell source for both cartilaginous zones. BMSCs were predifferentiated to chondrocytes, harvested and then grown on a porous calcium polyphosphate substrate in the presence of triiodothyronine (T3). T3 was withdrawn, and additional predifferentiated chondrocytes were placed on top of the construct and grown for 21 days. This protocol yielded two distinct zones: hyaline cartilage that accumulated proteoglycans and collagen type II, and calcified cartilage adjacent to the substrate that additionally accumulated mineral and collagen type X. Constructs with the calcified interface had comparable compressive strength to native sheep osteochondral tissue and higher interfacial shear strength compared to control without a calcified zone. This protocol improves on the existing scaffold-free approaches to cartilage tissue engineering by incorporating a calcified zone. Since this protocol employs no xenogeneic material, it will be appropriate for use in preclinical large-animal studies. Copyright © 2015 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  17. Hyaline cartilage thickness in radiographically normal cadaveric hips: comparison of spiral CT arthrographic and macroscopic measurements.

    Science.gov (United States)

    Wyler, Annabelle; Bousson, Valérie; Bergot, Catherine; Polivka, Marc; Leveque, Eric; Vicaut, Eric; Laredo, Jean-Denis

    2007-02-01

    To assess spiral multidetector computed tomographic (CT) arthrography for the depiction of cartilage thickness in hips without cartilage loss, with evaluation of anatomic slices as the reference standard. Permission to perform imaging studies in cadaveric specimens of individuals who had willed their bodies to science was obtained from the institutional review board. Two independent observers measured the femoral and acetabular hyaline cartilage thickness of 12 radiographically normal cadaveric hips (from six women and five men; age range at death, 52-98 years; mean, 76.5 years) on spiral multidetector CT arthrographic reformations and on coronal anatomic slices. Regions of cartilage loss at gross or histologic examination were excluded. CT arthrographic and anatomic measurements in the coronal plane were compared by using Bland-Altman representation and a paired t test. Differences between mean cartilage thicknesses at the points of measurement were tested by means of analysis of variance. Interobserver and intraobserver reproducibilities were determined. At CT arthrography, mean cartilage thickness ranged from 0.32 to 2.53 mm on the femoral head and from 0.95 to 3.13 mm on the acetabulum. Observers underestimated cartilage thickness in the coronal plane by 0.30 mm +/- 0.52 (mean +/- standard error) at CT arthrography (P cartilage thicknesses at the different measurement points was significant for coronal spiral multidetector CT arthrography and anatomic measurement of the femoral head and acetabulum and for sagittal and transverse CT arthrography of the femoral head (P cartilage thickness from the periphery to the center of the joint ("gradients") were found by means of spiral multidetector CT arthrography and anatomic measurement. Spiral multidetector CT arthrography depicts cartilage thickness gradients in radiographically normal cadaveric hips. (c) RSNA, 2007.

  18. Lipid domain formation and ligand-receptor distribution in lipid bilayer membranes investigated by atomic force microscopy

    DEFF Research Database (Denmark)

    Kaasgaard, Thomas; Mouritsen, O.G.; Jørgensen, K.

    2002-01-01

    A novel experimental technique, based on atomic force microscopy (AFM), is proposed to visualize the lateral organization of membrane systems in the nanometer range. The technique involves the use of a ligand-receptor pair, biotin-avidin, which introduces a height variation on a solid-supported l......A novel experimental technique, based on atomic force microscopy (AFM), is proposed to visualize the lateral organization of membrane systems in the nanometer range. The technique involves the use of a ligand-receptor pair, biotin-avidin, which introduces a height variation on a solid...

  19. Nanoengineered membrane electrode assembly interface

    Science.gov (United States)

    Song, Yujiang; Shelnutt, John A

    2013-08-06

    A membrane electrode structure suitable for use in a membrane electrode assembly (MEA) that comprises membrane-affixed metal nanoparticles whose formation is controlled by a photochemical process that controls deposition of the metal nanoparticles using a photocatalyst integrated with a polymer electrolyte membrane, such as an ionomer membrane. Impregnation of the polymer membrane with the photocatalyst prior to metal deposition greatly reduces the required amount of metal precursor in the deposition reaction solution by restricting metal reduction substantially to the formation of metal nanoparticles affixed on or near the surface of the polymer membrane with minimal formation of metallic particles not directly associated with the membrane.

  20. SNAP23, Syntaxin4, and vesicle-associated membrane protein 7 (VAMP7) mediate trafficking of membrane type 1-matrix metalloproteinase (MT1-MMP) during invadopodium formation and tumor cell invasion.

    Science.gov (United States)

    Williams, Karla C; McNeilly, Rachael E; Coppolino, Marc G

    2014-07-01

    Movement through the extracellular matrix (ECM) requires cells to degrade ECM components, primarily through the action of matrix metalloproteinases (MMPs). Membrane type 1-matrix metalloproteinase (MT1-MMP) has an essential role in matrix degradation and cell invasion and localizes to subcellular degradative structures termed invadopodia. Trafficking of MT1-MMP to invadopodia is required for the function of these structures, and here we examine the role of N-ethylmaleimide-sensitive factor-activating protein receptor (SNARE)-mediated membrane traffic in the transport of MT1-MMP to invadopodia. During invadopodium formation in MDA-MB-231 human breast cancer cells, increased association of SNAP23, Syntaxin4, and vesicle-associated membrane protein 7 (VAMP7) is detected by coimmunoprecipitation. Blocking the function of these SNAREs perturbs invadopodium-based ECM degradation and cell invasion. Increased level of SNAP23-Syntaxin4-VAMP7 interaction correlates with decreased Syntaxin4 phosphorylation. These results reveal an important role for SNARE-regulated trafficking of MT1-MMP to invadopodia during cellular invasion of ECM.

  1. Sphingolipid and cholesterol dependence of alphavirus membrane fusion - Lack of correlation with lipid raft formation in target liposomes

    NARCIS (Netherlands)

    Waarts, BL; Bittman, R; Wilschut, J

    2002-01-01

    Semliki Forest virus (SFV) and Sindbis virus (SIN) are enveloped viruses that infect their host cells by receptor-mediated endocytosis and subsequent fusion from within acidic endosomes. Fusion of the viral envelope requires the presence of both cholesterol and sphingolipids in the target membrane.

  2. Bacteriocin AS-48 binding to model membranes and pore formation as revealed by coarse-grained simulations

    NARCIS (Netherlands)

    Cruz, Victor L.; Ramos, Javier; Martinez-Salazar, Javier; Melo, Manuel N.

    2013-01-01

    Bacteriocin AS-48 is a membrane-interacting peptide that acts as a broad-spectrum antimicrobial against Gram-positive and Gram-negative bacteria. Prior Nuclear Magnetic Resonance experiments and the high resolution crystal structure of AS-48 have suggested a mechanism for the molecular activity of A

  3. Metabolic regulation of neutrophil spreading, membrane tubulovesicular extensions (cytonemes) formation and intracellular pH upon adhesion to fibronectin.

    Science.gov (United States)

    Galkina, Svetlana I; Sud'ina, Galina F; Klein, Thomas

    2006-08-01

    Circulating leukocytes have a round cell shape and roll along vessel walls. However, metabolic disorders can lead them to adhere to the endothelium and spread (flatten). We studied the metabolic regulation of adhesion, spreading and intracellular pH (pHi) of neutrophils (polymorphonuclear leukocytes) upon adhesion to fibronectin-coated substrata. Resting neutrophils adhered and spread on fibronectin. An increase in pHi accompanied neutrophil spreading. Inhibition of oxidative phosphorylation or inhibition of P- and F-type ATPases affected neither neutrophil spreading nor pHi. Inhibition of glucose metabolism or V-ATPase impaired neutrophil spreading, blocked the increase in the pHi and induced extrusion of membrane tubulovesicular extensions (cytonemes), anchoring cells to substrata. Omission of extracellular Na(+) and inhibition of chloride channels caused a similar effect. We propose that these tubulovesicular extensions represent protrusions of exocytotic trafficking, supplying the plasma membrane of neutrophils with ion exchange mechanisms and additional membrane for spreading. Glucose metabolism and V-type ATPase could affect fusion of exocytotic trafficking with the plasma membrane, thus controlling neutrophil adhesive state and pHi. Cl(-) efflux through chloride channels and Na(+) influx seem to be involved in the regulation of the V-ATPase by carrying out charge compensation for the proton-pumping activity and through V-ATPase in regulation of neutrophil spreading and pHi.

  4. The Solvent-Exposed C-Terminus of the Cytolysin A Pore-Forming Toxin Directs Pore Formation and Channel Function in Membranes.

    Science.gov (United States)

    Sathyanarayana, Pradeep; Desikan, Rajat; Ayappa, K Ganapathy; Visweswariah, Sandhya S

    2016-10-13

    Pore-forming toxins (PFTs) bind to cell membranes and form nanoscale pores that allow leakage of cellular components, resulting in cell death. The water-soluble, monomeric form of these toxins shows a dramatic conformational change during pore formation, as exemplified by crystal structures of the monomer and functional pore of cytolysin A (ClyA). The solvent-exposed, C-terminal residues of the protein are essential for activity, but the mechanism by which this region regulates pore formation remains unknown. We show here that deletion of the C-terminus of ClyA did not alter its ability to bind to the membrane or oligomerize in detergent. However, the truncated toxin lysed erythrocytes poorly, was more susceptible to proteolysis and thermal unfolding, and showed low calcein leakage from small unilamellar vesicles. Using fully atomistic molecular dynamics (MD) simulations, we find that deletion of C-terminal residues from the ClyA monomer significantly altered stability and unfolding trajectories in the transmembrane N-terminal helix, a region that is pivotal in maintaining the structural integrity of the helical bundle. MD simulations of pores with or without the C-terminus showed minor differences, implying that if oligomerization could be induced prior to the addition to vesicles, then an active pore could be generated. Via generation of oligomers in a detergent prior to the addition to vesicles, the truncated toxin could induce calcein leakage from vesicles, albeit to a lower extent. Therefore, regions of pore-forming toxins, not directly involved in the pore structure, are not passive players but have important roles in undergoing the transition through intermediary steps leading to successful pore formation in a membrane environment.

  5. Cartilage T2 assessment: differentiation of normal hyaline cartilage and reparative tissue after arthroscopic cartilage repair in equine subjects.

    Science.gov (United States)

    White, Lawrence M; Sussman, Marshall S; Hurtig, Mark; Probyn, Linda; Tomlinson, George; Kandel, Rita

    2006-11-01

    To prospectively assess T2 mapping characteristics of normal articular cartilage and of cartilage at sites of arthroscopic repair, including comparison with histologic results and collagen organization assessed at polarized light microscopy (PLM). Study protocol was compliant with the Canadian Council on Animal Care Guidelines and approved by the institutional animal care committee. Arthroscopic osteochondral autograft transplantation (OAT) and microfracture arthroplasty (MFx) were performed in knees of 10 equine subjects (seven female, three male; age range, 3-5 years). A site of arthroscopically normal cartilage was documented in each joint as a control site. Joints were harvested at 12 (n = 5) and 24 (n = 5) weeks postoperatively and were imaged at 1.5-T magnetic resonance (MR) with a 10-echo sagittal fast spin-echo acquisition. T2 maps of each site (21 OAT harvest, 10 MFx, 12 OAT plug, and 10 control sites) were calculated with linear least-squares curve fitting. Cartilage T2 maps were qualitatively graded as "organized" (normal transition of low-to-high T2 signal from deep to superficial cartilage zones) or "disorganized." Quantitative mean T2 values were calculated for deep, middle, and superficial cartilage at each location. Results were compared with histologic and PLM assessments by using kappa analysis. T2 maps were qualitatively graded as organized at 20 of 53 sites and as disorganized at 33 sites. Perfect agreement was seen between organized T2 and histologic findings of hyaline cartilage and between disorganized T2 and histologic findings of fibrous reparative tissue (kappa = 1.0). Strong agreement was seen between organized T2 and normal PLM findings and between disorganized T2 and abnormal PLM findings (kappa = .92). Quantitative assessment of the deep, middle, and superficial cartilage, respectively, showed mean T2 values of 53.3, 58.6, and 54.9 msec at reparative fibrous tissue sites and 40.7, 53.6, and 61.6 msec at hyaline cartilage sites. A

  6. A Facile Method to Prepare Double-Layer Isoporous Hollow Fiber Membrane by In Situ Hydrogen Bond Formation in the Spinning Line.

    Science.gov (United States)

    Noor, Nazia; Koll, Joachim; Radjabian, Maryam; Abetz, Clarissa; Abetz, Volker

    2016-03-01

    A double-layer hollow fiber is fabricated where an isoporous surface of polystyrene-block-poly(4-vinylpyridine) is fixed on a support layer by co-extrusion. Due to the sulfonation of the support layer material, delamination of the two layers is suppressed without increasing the number of subsequent processing steps for isoporous composite membrane formation. Electron microscope-energy-dispersive X-ray spectroscopy images unveil the existence of a high sulfur concentration in the interfacial region by which in-process H-bond formation between the layers is evidenced. For the very first time, our study reports a facile method to fabricate a sturdy isoporous double-layer hollow fiber.

  7. Spinning process variables and polymer solution effects in the die-swell phenomenon during hollow fiber membranes formation

    Directory of Open Access Journals (Sweden)

    Pereira C.C.

    2000-01-01

    Full Text Available During hollow fiber spinning many variables are involved whose effects are still not completely clear. However, its understanding is of great interest because the control of these variables may originate membranes with the desired morphologies and physical properties. In this work, the phase inversion process induced by the immersion precipitation technique was applied to prepare hollow fibers membranes. It was verified that some of the variables involved, can promote a visco-elastic polymer solution expansion, called die-swell phenomenon, which is undesired since it may lead to low reproducibility of the permeation properties. The effects of the distance between spinneret and precipitation bath, the bore liquid composition, and the polymer solution composition were analyzed and discussed in order to avoid this phenomenon. According to the results, it was verified that the parameters investigated might promote a delay precipitation, which restrained the visco-elastic expansion.

  8. Gliding Associated Proteins Play Essential Roles during the Formation of the Inner Membrane Complex of Toxoplasma gondii.

    Science.gov (United States)

    Harding, Clare R; Egarter, Saskia; Gow, Matthew; Jiménez-Ruiz, Elena; Ferguson, David J P; Meissner, Markus

    2016-02-01

    The inner membrane complex (IMC) of apicomplexan parasites is a specialised structure localised beneath the parasite's plasma membrane, and is important for parasite stability and intracellular replication. Furthermore, it serves as an anchor for the myosin A motor complex, termed the glideosome. While the role of this protein complex in parasite motility and host cell invasion has been well described, additional roles during the asexual life cycle are unknown. Here, we demonstrate that core elements of the glideosome, the gliding associated proteins GAP40 and GAP50 as well as members of the GAPM family, have critical roles in the biogenesis of the IMC during intracellular replication. Deletion or disruption of these genes resulted in the rapid collapse of developing parasites after initiation of the cell cycle and led to redistribution of other glideosome components.

  9. Gliding Associated Proteins Play Essential Roles during the Formation of the Inner Membrane Complex of Toxoplasma gondii.

    Directory of Open Access Journals (Sweden)

    Clare R Harding

    2016-02-01

    Full Text Available The inner membrane complex (IMC of apicomplexan parasites is a specialised structure localised beneath the parasite's plasma membrane, and is important for parasite stability and intracellular replication. Furthermore, it serves as an anchor for the myosin A motor complex, termed the glideosome. While the role of this protein complex in parasite motility and host cell invasion has been well described, additional roles during the asexual life cycle are unknown. Here, we demonstrate that core elements of the glideosome, the gliding associated proteins GAP40 and GAP50 as well as members of the GAPM family, have critical roles in the biogenesis of the IMC during intracellular replication. Deletion or disruption of these genes resulted in the rapid collapse of developing parasites after initiation of the cell cycle and led to redistribution of other glideosome components.

  10. Formation of composite films of ion-track membranes embedded with oblique Cu nanowires for anisotropic infrared absorption

    Energy Technology Data Exchange (ETDEWEB)

    Koshikawa, Hiroshi [Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan)], E-mail: koshikawa.hiroshi@jaea.go.jp; Maekawa, Yasunari [Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Usui, Hiroaki [Tokyo University of Agriculture and Technology, 2-24-16 Naka-machi, Koganei, Tokyo 184-8588 (Japan)

    2008-04-15

    Composite films of poly(ethylene terephthalate) (PET) embedded with Cu nanowires were prepared by electroplating ion-track PET membranes. PET films were irradiated with 450 MeV {sup 129}Xe{sup 23+} ions with a direction of 45{sup o} from the film normal, and then etched with sodium hydroxide solution to form thin pores of 1 {mu}m diameter. Cu was filled into the pores by electroplating in a copper sulfate solution to form Cu nanowires embedded in a direction tilted from the film normal. The composite membrane showed anisotropic infrared absorption in the in-plane direction, having the transmission axis in the direction normal to the ion incidence.

  11. In-line coupling of microextractions across polymer inclusion membranes to capillary zone electrophoresis for rapid determination of formate in blood samples.

    Science.gov (United States)

    Pantůčková, Pavla; Kubáň, Pavel; Boček, Petr

    2015-08-05

    Polymer inclusion membranes (PIMs) have several important features, i.e., PIMs are dry and non-porous membranes, which can be prepared ahead of use and stored without noticeable deterioration in extraction performance. In this contribution, in-line coupling of microextractions across PIMs to a separation method for clinical purposes was demonstrated for the first time. Formate (the major metabolite in methanol poisoning) was determined in undiluted human serum and whole blood by capillary zone electrophoresis (CZE) with simultaneous capacitively coupled contactless conductivity detection (C(4)D) and UV-Vis detection. A purpose-made microextraction device with PIM was coupled to a commercial CZE instrument in order to ensure complete automation of the entire analytical procedure, i.e., of formate extraction, injection, CZE separation and quantification. PIMs for formate extractions consisted of 60% (w/w) cellulose triacetate as base polymer and 40% (w/w) Aliquat™ 336 as anion carrier. The method was characterized by good repeatability of peak areas (≤7.0%) and migration times (≤0.8%) and by good linearity of calibration curves (r(2) = 0.993-0.999). Limits of detection in various matrices ranged from 15 to 54 μM for C(4)D and from 200 to 635 μM for UV-Vis detection and were sufficiently low to clearly distinguish between endogenous and toxic levels of formate in healthy and methanol intoxicated individuals. In addition, PIMs proved that they may act as phase interfaces with excellent long-term stability since once prepared, they retained their extractions properties for, at least, two months of storage.

  12. Evaluation of fouling formation and evolution on hollow fibre membrane: effects of ageing and chemical exposure on biofoulant.

    Science.gov (United States)

    Xu, Qianhui; Ye, Yun; Chen, Vicki; Wen, Xianghua

    2015-01-01

    Bio-deposition and biofouling, a major challenge for membrane filtration, is still not fully understood due to its complex structure and intricate evolution with time and chemical environment. In this work, diluted sludge from an anaerobic bioreactor with low mixed liquor suspended solid (MLSS) concentration was filtered for 3.5 h to form initial fouling layers which were then exposed to various solution environments for 17 h. Apart from monitoring the hydraulic resistance of membrane fouling, a real time direct observation (DO) technique was applied to monitor the change of thickness in the fouling layer. The cohesion and adhesion of different fouling layer were investigated by monitoring the transmembrane pressure (TMP) and thickness change after applying relaxation (cessation of filtration) and backwash. It was found that TMPs and resistances of the aged fouling layers increased significantly after 17 h filtration. All the aged fouling layers exhibited lower compressibility as a result of more soluble microbial products (SMP) and extracellular polymeric substances (EPS) excretion, biofilm growth. From in situ imaging, the fouling on the membrane surface appeared to be inhomogeneous from the inner (lumen) surface outwards. During long term filtration of fouling layer with Milli-Q water, direct observation (DO) results indicated the reorganization of the fouling layer in terms of peeling, rolling over and re-depositing on the membrane surface, resulting into more compressed fouling layers with higher resistances. Confocal Laser Scanning Microscopy (CLSM) analysis of aged fouling layers also indicated that the dead/total ratio of microorganisms was not uniform and increased gradually from the bottom to the top of the fouling layers.

  13. In situ formation and assembly of CdS nanocrystallites into polyhedrons on Eggshell membrane at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Su, Huilan; Xu, Jia; Chen, Jianjun; Zhang, Di [Shanghai Jiao Tong University, State Key Lab of Metal Matrix Composites, Shanghai (China); Moon, Won-Jin [Gwangjun Center, Korea Basic Science Institute, Buk-gu, Gwangju (Korea, Republic of)

    2012-01-15

    A room-temperature soakage procedure was carried out to successfully form and assemble CdS nanocrystallites into polyhedrons on the eggshell membrane (ESM). Based on the biomaterial ESM served as the reactive substrate and some ESM biomacromolecules acted as the surfactants, CdS nanocrystallites were in situ formed, further assembled into well-distributed polyhedrons, and finally performed CdS-ESM hybrid nanocomposites. This moderate bioinspired strategy would also be of great value to prepare novel functional nanocomposites. (orig.)

  14. A novel approach to regulate cell membrane permeability for ATP and NADH formation in Saccharomyces cerevisiae induced by air cold plasma

    Science.gov (United States)

    Xiaoyu, DONG; Tingting, LIU; Yuqin, XIONG

    2017-02-01

    Air cold plasma has been used as a novel method for enhancing microbial fermentation. The aim of this work was to explore the effect of plasma on membrane permeability and the formation of ATP and NADH in Saccharomyces cerevisiae, so as to provide valuable information for large-scale application of plasma in the fermentation industry. Suspensions of S. cerevisiae cells were exposed to air cold plasma for 0, 1, 2, 3, 4 and 5 min, and then subjected to various analyses prior to fermentation (0 h) and at the 9 and 21 h stages of fermentation. Compared with non-exposed cells, cells exposed to plasma for 1 min exhibited a marked increase in cytoplasmic free Ca2+ concentration as a result of the significant increase in membrane potential prior to fermentation. At the same time, the ATP level in the cell suspension decreased by about 40%, resulting in a reduction of about 60% in NADH prior to culturing. However, the levels of ATP and NADH in the culture at the 9 and 21 h fermentation stages were different from the level at 0 h. Taken together, the results indicated that exposure of S. cerevisiae to air cold plasma could increase its cytoplasmic free Ca2+ concentration by improving the cell membrane potential, consequently leading to changes in ATP and NADH levels. Supported by National Natural Science Foundation of China (Nos. 21246012, 21306015 and 21476032).

  15. Early events in the generation of autophagosomes are required for the formation of membrane structures involved in hepatitis C virus genome replication.

    Science.gov (United States)

    Mohl, Bjorn-Patrick; Bartlett, Christopher; Mankouri, Jamel; Harris, Mark

    2016-03-01

    Hepatitis C virus (HCV) infection has been shown to induce autophagy but the mechanisms underpinning this process remain to be elucidated. Induction of autophagy requires the class III phosphatidylinositol 3-kinase, Vps34, which produces phosphatidylinositol 3-phosphate (PI3P) within the endoplasmic reticulum (ER) membrane. This recruits proteins with PI3P binding domains such as the double-FYVE-containing protein 1 (DFCP1). DFCP1 generates cup-shaped protrusions from the ER membrane, termed omegasomes, which provide a platform for the production of autophagosomes. Here we present data demonstrating that both Vps34 and DFCP1 are required for HCV genome replication, in the context of both a subgenomic replicon and virus infection, but did not affect virus entry or initial translation. Using live cell fluorescence microscopy we demonstrated that early during HCV infection the nascent viral genome replication complexes (identified by using non-structural protein NS5A as a marker) transiently colocalize with DFCP1-positive punctae (omegasomes), before the two structures move apart from each other. This observation is reminiscent of the transient association of LC3 and DFCP1 during omegasome formation, and therefore we propose that omegasomes are utilized by HCV to generate the double-membrane vesicles which are the hallmark of HCV replication complexes.

  16. Reconstruction of Hyaline Cartilage Deep Layer Properties in 3-Dimensional Cultures of Human Articular Chondrocytes.

    Science.gov (United States)

    Nanduri, Vibudha; Tattikota, Surendra Mohan; T, Avinash Raj; Sriramagiri, Vijaya Rama Rao; Kantipudi, Suma; Pande, Gopal

    2014-06-01

    Articular cartilage (AC) injuries and malformations are commonly noticed because of trauma or age-related degeneration. Many methods have been adopted for replacing or repairing the damaged tissue. Currently available AC repair methods, in several cases, fail to yield good-quality long-lasting results, perhaps because the reconstructed tissue lacks the cellular and matrix properties seen in hyaline cartilage (HC). To reconstruct HC tissue from 2-dimensional (2D) and 3-dimensional (3D) cultures of AC-derived human chondrocytes that would specifically exhibit the cellular and biochemical properties of the deep layer of HC. Descriptive laboratory study. Two-dimensional cultures of human AC-derived chondrocytes were established in classical medium (CM) and newly defined medium (NDM) and maintained for a period of 6 weeks. These cells were suspended in 2 mm-thick collagen I gels, placed in 24-well culture inserts, and further cultured up to 30 days. Properties of chondrocytes, grown in 2D cultures and the reconstructed 3D cartilage tissue, were studied by optical and scanning electron microscopic techniques, immunohistochemistry, and cartilage-specific gene expression profiling by reverse transcription polymerase chain reaction and were compared with those of the deep layer of native human AC. Two-dimensional chondrocyte cultures grown in NDM, in comparison with those grown in CM, showed more chondrocyte-specific gene activity and matrix properties. The NDM-grown chondrocytes in 3D cultures also showed better reproduction of deep layer properties of HC, as confirmed by microscopic and gene expression analysis. The method used in this study can yield cartilage tissue up to approximately 1.6 cm in diameter and 2 mm in thickness that satisfies the very low cell density and matrix composition properties present in the deep layer of normal HC. This study presents a novel and reproducible method for long-term culture of AC-derived chondrocytes and reconstruction of cartilage

  17. Granuloma hialinizante de pulmão recidivante Recurrent pulmonary hyalinizing granuloma

    Directory of Open Access Journals (Sweden)

    Guilherme D'Andréa Saba Arruda

    2010-10-01

    Full Text Available Relatamos o caso de um paciente de 61 anos, masculino, internado com objetivo de exérese de massa pulmonar para estudo anatomopatológico. O paciente apresentara anteriormente um quadro de febre, tosse seca e dor torácica, associado à presença de massas pulmonares detectadas por radiografia de tórax, tendo sido submetido em duas ocasiões (1976 e 1981 a toracotomia para a investigação diagnóstica, sem diagnóstico anatomopatológico conclusivo. A TC de tórax revelou volumosas massas com áreas de calcificação em ambos os campos pulmonares. O material do estudo anatomopatológico foi compatível com granuloma hialinizante de pulmão. No pós-operatório, o paciente apresentou vários episódios de broncoespasmo que foram revertidos com medicação sintomática. Foi mantido com prednisona na dose de 40 mg/dia com boa evolução clínica até o envio deste relato.We report the case of a 61-year-old male patient who underwent surgical excision of a lung mass for anatomopathological study. The patient had previously presented with fever, dry cough, and chest pain, together with lung masses detected by chest X-ray, and had undergone thoracotomy for diagnostic investigation on two occasions (1976 and 1981, although a conclusive diagnosis had not been made. A CT scan of the chest revealed large masses with areas of calcification in both lung fields. The anatomopathological study was consistent with pulmonary hyalinizing granuloma. In the postoperative period, the patient experienced several episodes of bronchospasm, which was reversible with the use of symptomatic medication. At this writing, the patient was receiving maintenance therapy with prednisone (40 mg/day and had shown clinical improvement.

  18. pH-Dependent Formation and Disintegration of the Influenza A Virus Protein Scaffold To Provide Tension for Membrane Fusion.

    Science.gov (United States)

    Batishchev, O V; Shilova, L A; Kachala, M V; Tashkin, V Y; Sokolov, V S; Fedorova, N V; Baratova, L A; Knyazev, D G; Zimmerberg, J; Chizmadzhev, Y A

    2015-10-14

    Influenza virus is taken up from a pH-neutral extracellular milieu into an endosome, whose contents then acidify, causing changes in the viral matrix protein (M1) that coats the inner monolayer of the viral lipid envelope. At a pH of ~6, M1 interacts with the viral ribonucleoprotein (RNP) in a putative priming stage; at this stage, the interactions of the M1 scaffold coating the lipid envelope are intact. The M1 coat disintegrates as acidification continues to a pH of ~5 to clear a physical path for the viral genome to transit from the viral interior to the cytoplasm. Here we investigated the physicochemical mechanism of M1's pH-dependent disintegration. In neutral media, the adsorption of M1 protein on the lipid bilayer was electrostatic in nature and reversible. The energy of the interaction of M1 molecules with each other in M1 dimers was about 10 times as weak as that of the interaction of M1 molecules with the lipid bilayer. Acidification drives conformational changes in M1 molecules due to changes in the M1 charge, leading to alterations in their electrostatic interactions. Dropping the pH from 7.1 to 6.0 did not disturb the M1 layer; dropping it lower partially desorbed M1 because of increased repulsion between M1 monomers still stuck to the membrane. Lipid vesicles coated with M1 demonstrated pH-dependent rupture of the vesicle membrane, presumably because of the tension generated by this repulsive force. Thus, the disruption of the vesicles coincident with M1 protein scaffold disintegration at pH 5 likely stretches the lipid membrane to the point of rupture, promoting fusion pore widening for RNP release. Influenza remains a top killer of human beings throughout the world, in part because of the influenza virus's rapid binding to cells and its uptake into compartments hidden from the immune system. To attack the influenza virus during this time of hiding, we need to understand the physical forces that allow the internalized virus to infect the cell. In

  19. Preparation of PTFE-based fuel cell membranes by combining latent track formation technology with graft polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Masaru [Quantum Beam Science Directorate, Japan Atomic Energy Agency (JAEA), 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)], E-mail: yoshida.masaru@jaea.go.jp; Kimura, Yosuke [Graduate School of Engineering, Gunma University, 1-5-1 Tenjin, Kiryu, Gunma 376-8515 (Japan); Chen, Jinhua; Asano, Masaharu; Maekawa, Yasunari [Quantum Beam Science Directorate, Japan Atomic Energy Agency (JAEA), 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)

    2009-12-15

    Swift heavy 56 MeV {sup 15}N{sup 3+} ions were generated with particle fluences of 0, 3x10{sup 6}, 3x10{sup 7}, 3x10{sup 8}, 3x10{sup 9} ions/cm{sup 2} to form a latent track zone in a 25-{mu}m-thick film of polytetrafluoroethylene (iPTFE). Styrene (St) was then grafted onto the iPTFE films by UV-irradiation or pre-{gamma}-irradiation, and after sulfonation iPTFE-based proton-conducting membranes were obtained, here called, iPTFE-g(UV)-PStSA and iPTFE-g({gamma})-PStSA membranes, respectively, which had a straight cylindrical damage zone around the ion path. The degree of grafting was found to be about 7.5% with a particle fluence of 3x10{sup 7} ions/cm{sup 2} and with either the UV-method or the {gamma}-method. The ion-exchange capacity, proton conductivity in the thickness direction, MeOH permeability, tensile strength and elongation at break of the obtained iPTFE-g(UV)-PStSA membrane were 0.50 mmol/g, 0.06 S/cm, 0.15x10{sup -6} cm{sup 2}/s, 50 MPa and 600%, in contrast to 0.06 mmol/g, 0.06 S/cm, 0.35x10{sup -6} cm{sup 2}/s, 19 MPa and 210% for the iPTFE-g({gamma})-PStSA membrane, respectively. In comparison, the Nafion 112 measured in our laboratory exhibited an ion-exchange capacity of 0.91 mmol/g, a proton conductivity of 0.06 S/cm, a MeOH permeability of 1.02x10{sup -6} cm{sup 2}/s, a tensile strength of 35 MPa and an elongation at break of 295%. It can be concluded from these data that the lower crossover of MeOH, the same proton conductibility, the lower ion-exchange capacity, and the superior mechanical properties of the UV-grafted proton-conducting membranes compared to the Nafion make them promising materials for widespread application in direct methanol fuel cells. On the other hand, the tests of mechanical strength showed that the PTFE base film is subject to degradation by the ion-beam irradiation as well as the {gamma}-irradiation.

  20. Potential Prepore Trimer Formation by the Bacillus thuringiensis Mosquito-specific Toxin: MOLECULAR INSIGHTS INTO A CRITICAL PREREQUISITE OF MEMBRANE-BOUND MONOMERS.

    Science.gov (United States)

    Sriwimol, Wilaiwan; Aroonkesorn, Aratee; Sakdee, Somsri; Kanchanawarin, Chalermpol; Uchihashi, Takayuki; Ando, Toshio; Angsuthanasombat, Chanan

    2015-08-21

    The insecticidal feature of the three-domain Cry δ-endotoxins from Bacillus thuringiensis is generally attributed to their capability to form oligomeric pores, causing lysis of target larval midgut cells. However, the molecular description of their oligomerization process has not been clearly defined. Here a stable prepore of the 65-kDa trypsin-activated Cry4Ba mosquito-specific toxin was established through membrane-mimetic environments by forming an ∼200-kDa octyl-β-D-glucoside micelle-induced trimer. The SDS-resistant trimer caused cytolysis to Sf9 insect cells expressing Aedes-mALP (a Cry4Ba receptor) and was more effective than a toxin monomer in membrane perturbation of calcein-loaded liposomes. A three-dimensional model of toxin trimer obtained by negative-stain EM in combination with single-particle reconstruction at ∼5 nm resolution showed a propeller-shaped structure with 3-fold symmetry. Fitting the three-dimensional reconstructed EM map with a 100-ns molecular dynamics-simulated Cry4Ba structure interacting with an octyl-β-D-glucoside micelle showed relative positioning of individual domains in the context of the trimeric complex with a major protrusion from the pore-forming domain. Moreover, high-speed atomic force microscopy imaging at nanometer resolution and a subsecond frame rate demonstrated conformational transitions from a propeller-like to a globularly shaped trimer upon lipid membrane interactions, implying prepore-to-pore conversion. Real-time trimeric arrangement of monomers associated with L-α-dimyristoylphosphatidylcholine/3-[(3-cholamidopropyl)dimethylammonio]-2-hydroxy-1-propanesulfonic acid bicelle membranes was also envisaged by successive high-speed atomic force microscopy imaging, depicting interactions among three individual subunits toward trimer formation. Together, our data provide the first pivotal insights into the structural requirement of membrane-induced conformational changes of Cry4Ba toxin monomers for the

  1. Annulus Fibrosus Can Strip Hyaline Cartilage End Plate from Subchondral Bone: A Study of the Intervertebral Disk in Tension.

    Science.gov (United States)

    Balkovec, Christian; Adams, Michael A; Dolan, Patricia; McGill, Stuart M

    2015-10-01

    Study Design Biomechanical study on cadaveric spines. Objective Spinal bending causes the annulus to pull vertically (axially) on the end plate, but failure mechanisms in response to this type of loading are poorly understood. Therefore, the objective of this study was to identify the weak point of the intervertebral disk in tension. Methods Cadaveric motion segments (aged 79 to 88 years) were dissected to create midsagittal blocks of tissue, with ∼10 mm of bone superior and inferior to the disk. From these blocks, 14 bone-disk-bone slices (average 4.8 mm thick) were cut in the frontal plane. Each slice was gripped by its bony ends and stretched to failure at 1 mm/s. Mode of failure was recorded using a digital camera. Results Of the 14 slices, 10 failed by the hyaline cartilage being peeled off the subchondral bone, with the failure starting opposite the lateral annulus and proceeding medially. Two slices failed by rupturing of the trabecular bone, and a further two failed in the annulus. Conclusions The hyaline cartilage-bone junction is the disk's weak link in tension. These findings provide a plausible mechanism for the appearance of bone and cartilage fragments in herniated material. Stripping cartilage from the bony end plate would result in the herniated mass containing relatively stiff cartilage that does not easily resorb.

  2. Effect of exercise on thicknesses of mature hyaline cartilage, calcified cartilage, and subchondral bone of equine tarsi.

    Science.gov (United States)

    Tranquille, Carolyne A; Blunden, Antony S; Dyson, Sue J; Parkin, Tim D H; Goodship, Allen E; Murray, Rachel C

    2009-12-01

    OBJECTIVE-To investigate effects of exercise on hyaline cartilage (HC), calcified cartilage (CC), and subchondral bone (SCB) thickness patterns of equine tarsi. SAMPLE POPULATION-30 tarsi from cadavers of horses with known exercise history. PROCEDURES-Tarsi were assigned to 3 groups according to known exercise history as follows: pasture exercise only (PE tarsi), low-intensity general-purpose riding exercise (LE tarsi), and high-intensity elite competition riding exercise (EE tarsi). Osteochondral tissue from distal tarsal joints underwent histologic preparation. Hyaline cartilage, CC, and SCB thickness were measured at standard sites at medial, midline, and lateral locations across joints with a histomorphometric technique. RESULTS-HC, CC, and SCB thickness were significantly greater at all sites in EE tarsi, compared with PE tarsi; this was also true when LE tarsi were compared with PE tarsi. At specific sites, HC, CC, and SCB were significantly thicker in EE tarsi, compared with LE tarsi. Along the articular surface of the proximal aspect of the third metatarsal bone, SCB was thickest in EE tarsi and thinnest in LE tarsi; increases were greatest at sites previously reported to undergo peak strains and osteochondral damage. CONCLUSIONS AND CLINICAL RELEVANCE-Increased exercise was associated with increased HC, CC, and SCB thickness in mature horses. At sites that undergo high compressive strains, with a reported predisposition to osteoarthritic change, there was increased CC and SCB thickness. These results may provide insight into the interaction between adaptive response to exercise and pathological change.

  3. Effect of low-dose irradiation on structural and mechanical properties of hyaline cartilage-like fibrocartilage.

    Science.gov (United States)

    Öncan, Tevfik; Demirağ, Burak; Ermutlu, Cenk; Yalçinkaya, Ulviye; Özkan, Lütfü

    2013-01-01

    The aim of this study was to analyze the effect of low-dose irradiation on fibrous cartilage and to obtain a hyaline cartilage-like fibrocartilage (HCLF) with similar structural and mechanical properties to hyaline cartilage. An osteochondral defect was created in 40 knees of 20 rabbits. At the 7th postoperative day, a single knee of each rabbit was irradiated with a total dose of 5.0 Gy in 1.0 Gy fractions for 5 days (radiotherapy group), while the other knee was not irradiated (control group). Rabbits were then divided into four groups of 5 rabbits each. The first three groups were sacrificed at the 4th, 8th and the 12th postoperative weeks and cartilage defects were macroscopically and microscopically evaluated. The remaining group of 5 rabbits was sacrificed at the 12th week and biomechanical compression tests were performed on the cartilage defects. There was no significant biomechanical difference between the radiotherapy and the control group (p=0.686). There was no significant macroscopic and microscopic difference between groups (p=0.300). Chondrocyte clustering was observed in the irradiated group. Low-dose irradiation does not affect the mechanical properties of HCLF in vivo. However, structural changes such as chondrocyte clustering were observed.

  4. A preclinical evaluation of an autologous living hyaline-like cartilaginous graft for articular cartilage repair: a pilot study.

    Science.gov (United States)

    Peck, Yvonne; He, Pengfei; Chilla, Geetha Soujanya V N; Poh, Chueh Loo; Wang, Dong-An

    2015-11-09

    In this pilot study, an autologous synthetic scaffold-free construct with hyaline quality, termed living hyaline cartilaginous graft (LhCG), was applied for treating cartilage lesions. Implantation of autologous LhCG was done at load-bearing regions of the knees in skeletally mature mini-pigs for 6 months. Over the course of this study, significant radiographical improvement in LhCG treated sites was observed via magnetic resonance imaging. Furthermore, macroscopic repair was effected by LhCG at endpoint. Microscopic inspection revealed that LhCG engraftment restored cartilage thickness, promoted integration with surrounding native cartilage, produced abundant cartilage-specific matrix molecules, and re-established an intact superficial tangential zone. Importantly, the repair efficacy of LhCG was quantitatively shown to be comparable to native, unaffected cartilage in terms of biochemical composition and biomechanical properties. There were no complications related to the donor site of cartilage biopsy. Collectively, these results imply that LhCG engraftment may be a viable approach for articular cartilage repair.

  5. Which cartilage is regenerated, hyaline cartilage or fibrocartilage? Non-invasive ultrasonic evaluation of tissue-engineered cartilage.

    Science.gov (United States)

    Hattori, K; Takakura, Y; Ohgushi, H; Habata, T; Uematsu, K; Takenaka, M; Ikeuchi, K

    2004-09-01

    To investigate ultrasonic evaluation methods for detecting whether the repair tissue is hyaline cartilage or fibrocartilage in new cartilage regeneration therapy. We examined four experimental rabbit models: a spontaneous repair model (group S), a large cartilage defect model (group L), a periosteal graft model (group P) and a tissue-engineered cartilage regeneration model (group T). From the resulting ultrasonic evaluation, we used %MM (the maximum magnitude of the measurement area divided by that of the intact cartilage) as a quantitative index of cartilage regeneration. The results of the ultrasonic evaluation were compared with the histological findings and histological score. The %MM values were 61.1 +/- 16.5% in group S, 29.8 +/- 15.1% in group L, 36.3 +/- 18.3% in group P and 76.5 +/- 18.7% in group T. The results showed a strong similarity to the histological scoring. The ultrasonic examination showed that all the hyaline-like cartilage in groups S and T had a high %MM (more than 60%). Therefore, we could define the borderline between the two types of regenerated cartilage by the %MM.

  6. Biochemical characterisation of navicular hyaline cartilage, navicular fibrocartilage and the deep digital flexor tendon in horses with navicular disease.

    Science.gov (United States)

    Viitanen, M; Bird, J; Smith, R; Tulamo, R-M; May, S A

    2003-10-01

    The study hypothesis was that navicular disease is a process analogous to degenerative joint disease, which leads to changes in navicular fibrocartilage and in deep digital flexor tendon (DDFT) matrix composition and that the process extends to the adjacent distal interphalangeal joint. The objectives were to compare the biochemical composition of the navicular articular and palmar cartilages from 18 horses with navicular disease with 49 horses with no history of front limb lameness, and to compare navicular fibrocartilage with medial meniscus of the stifle and collateral cartilage of the hoof. Cartilage oligomeric matrix protein (COMP), deoxyribonucleic acid (DNA), total glycosaminoglycan (GAG), metalloproteinases MMP-2 and MMP-9 and water content in tissues were measured. Hyaline cartilage had the highest content of COMP and COMP content in hyaline cartilage and tendon was higher in lame horses than in sound horses (phyaline cartilage was higher in lame horses than in sound horses. The MMP-2 amounts were significantly higher in tendons compared to other tissue types. Overall, 79% of the lame horses with lesions had MMP-9 in their tendons and the amount was higher than in sound horses (phyaline and fibrocartilage as well as the DDFT with potential implications for the pathogenesis and management of the condition.

  7. Key Residues of Outer Membrane Protein OprI Involved in Hexamer Formation and Bacterial Susceptibility to Cationic Antimicrobial Peptides

    OpenAIRE

    Chang, Ting-Wei; Wang, Chiu-Feng; Huang, Hsin-Jye; Wang, Iren; Hsu, Shang-Te Danny; Liao, You-Di

    2015-01-01

    Antimicrobial peptides (AMPs) are important components of the host innate defense mechanism against invading pathogens. Our previous studies have shown that the outer membrane protein, OprI from Pseudomonas aeruginosa or its homologue, plays a vital role in the susceptibility of Gram-negative bacteria to cationic α-helical AMPs (Y. M. Lin, S. J. Wu, T. W. Chang, C. F. Wang, C. S. Suen, M. J. Hwang, M. D. Chang, Y. T. Chen, Y. D. Liao, J Biol Chem 285:8985–8994, 2010, http://dx.doi.org/10.1074...

  8. Channel Formation by CarO, the Carbapenem Resistance-Associated Outer Membrane Protein of Acinetobacter baumannii

    OpenAIRE

    2005-01-01

    It has been recently shown that resistance to both imipenem and meropenem in multidrug-resistant clinical strains of Acinetobacter baumannii is associated with the loss of a heat-modifiable 25/29-kDa outer membrane protein, called CarO. This study aimed to investigate the channel-forming properties of CarO. Mass spectrometry analyses of this protein band detected another 25-kDa protein (called Omp25), together with CarO. Both proteins presented similar physicochemical parameters (Mw and pI). ...

  9. Effect of the Mode of Application of Cryopreserved Human Amniotic Membrane on Adhesion Formation after Abdomino-Pelvic Surgery in a Mouse Model.

    Science.gov (United States)

    Nassif, Joseph; Abbasi, Sehrish A; Kechli, Mohamad Karim; Boutary, Suzan S; Ghulmiyyah, Labib; Khalifeh, Ibrahim; Abou Ghaddara, Hussein; Nassar, Anwar H

    2016-01-01

    Adhesions after abdomino-pelvic surgery are a cause of morbidity and reoperations. The use of human amniotic membrane (HAM) for adhesion prevention has given controversial results. The mode of administration of the amniotic membrane has not been well studied. This study assessed the efficacy of two modes of application of cryopreserved HAM, patch or fragmented in Lactated Ringer (LR) solution, for the prevention of pelvic adhesion formation postabdomino-pelvic surgery in a mice model. After a midline laparotomy incision, a small cautery lesion was done on each side of the abdominal wall peritoneum in mice. In Group A (control; n = 42), the abdomen was closed directly, Group B (n = 42) received 2.5 ml of LR prior to closure. In Groups C (n = 42) and D (n = 42), a 2 cm × 2 cm patch of HAM and another one fragmented and dispersed in 2.5 ml of LR were applied prior to closure, respectively. Two weeks later, a laparotomy was performed, and gross and pathological evaluation of adhesions, fibrosis, angiogenesis, and inflammation were conducted. Group D exhibited a significantly lower rate of gross adhesion formation. Fibrosis was significantly lowest in Group C as compared to the control. Group B had the lowest vascular formation in the adhesions. The use of HAM fragmented in LR solution is associated with a significantly lower incidence of postoperative adhesions in mice when compared to LR alone, HAM patch, or control. The mechanism of action of this reduction needs to be elucidated by future studies.

  10. Formation of chelating agent driven anodized TiO{sub 2} nanotubular membrane and its photovoltaic application

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Subarna; Misra, Mano; Mohapatra, Susanta K; Howard, Cameron [Chemical and Materials Engineering/MS 388, University of Nevada, Reno, NV 89557 (United States); Mohapatra, Srikanta K [NM Institute of Engineering and Technology, Bhubaneswar 751009 (India); Kamilla, Sushanta K, E-mail: Misra@unr.edu [Institute of Technical Education and Research, Bhubaneswar 751030 (India)

    2010-04-09

    Titania (TiO{sub 2}) nanotubular arrays provide an exciting material for dye sensitizing solar cells (DSSC) because of their large surface area, lower recombination losses, and fast charge transport properties along the nanotubes. In this paper, design of a next generation DSSC using a TiO{sub 2} nanotubular membrane is discussed. A single step, green process is developed to produce stable large area, free-standing TiO{sub 2} nanotubular films (in a short time, 30-60 min) by anodizing Ti using an organic electrolyte, containing disodium salt of ethylene diaminetetraacetic acid (Na{sub 2}[H{sub 2}EDTA]) as complexing agent, and subsequent drying. Transparent, crack-free TiO{sub 2} films, 20-41 {mu}m thick containing ordered hexagonal TiO{sub 2} nanotubes are achieved by this process. Films having a geometrical area up to 16.5 cm{sup 2} with pore openings of 182 nm have been obtained. These films have been etched to form membranes which provide an exciting prospect for front side illuminated DSSC with good mass and photon transport properties as well as wettability. A photovoltaic efficiency of 2.7% is achieved using a front side illuminated DSSC compared to 1.77% using back side illumination.

  11. Transplantation of autologous endothelial progenitor cells in porous PLGA scaffolds create a microenvironment for the regeneration of hyaline cartilage in rabbits.

    Science.gov (United States)

    Chang, N-J; Lam, C-F; Lin, C-C; Chen, W-L; Li, C-F; Lin, Y-T; Yeh, M-L

    2013-10-01

    Repairing articular cartilage is clinically challenging. We investigated a simple, effective and clinically feasible cell-based therapeutic approach using a poly(lactide-co-glycolide) (PLGA) scaffold seeded with autologous endothelial progenitor cells (EPC) to repair a full-thickness osteochondral defect in rabbits using a one-step surgery. EPC obtained by purifying a small amount of peripheral blood from rabbits were seeded into a highly porous, biocompatible PLGA scaffold, namely, EPC-PLGA, and implanted into the osteochondral defect in the medial femoral condyle. Twenty two rabbits were randomized into one of three groups: the empty defect group (ED), the PLGA-only group or the EPC-PLGA group. The defect sites were evaluated 4 and 12 weeks after implantation. At the end of testing, only the EPC-PLGA group showed the development of new cartilage tissue with a smooth, transparent and integrated articular surface. Moreover, histological analysis showed obvious differences in cartilage regeneration. At week 4, the EPC-PLGA group showed considerably higher TGF-β2 and TGF-β3 expression, a greater amount of synthesized glycosaminoglycan (GAG) content, and a higher degree of osteochondral angiogenesis in repaired tissues. At week 12, the EPC-PLGA group showed enhanced hyaline cartilage regeneration with a normal columnar chondrocyte arrangement, higher SOX9 expression, and greater GAG and collagen type II (COLII) content. Moreover, the EPC-PLGA group showed organized osteochondral integration, the formation of vessel-rich tubercular bone and significantly higher bone volume per tissue volume and trabecular thickness (Tb.Th). The present EPC-PLGA cell delivery system generates a suitable in situ microenvironment for osteochondral regeneration without the supplement of exogenous growth factors. Copyright © 2013 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  12. In-situ birth of MSCs multicellular spheroids in poly(L-glutamic acid)/chitosan scaffold for hyaline-like cartilage regeneration.

    Science.gov (United States)

    Zhang, Kunxi; Yan, Shifeng; Li, Guifei; Cui, Lei; Yin, Jingbo

    2015-12-01

    The success of mesenchymal stem cells (MSCs) based articular cartilage tissue engineering is limited by the presence of fibrous tissue in generated cartilage, which is associated with the current scaffold strategy that promotes cellular adhesion and spreading. Here we design a non-fouling scaffold based on amide bonded poly(l-glutamic acid) (PLGA) and chitosan (CS) to drive adipose stem cells (ASCs) to aggregate to form multicellular spheroids with diameter of 80-110 μm in-situ. To illustrate the advantage of the present scaffolds, a cellular adhesive scaffold based on the same amide bonded PLGA and CS was created through a combination of air-drying and freeze-drying to limit the hydration effect while also achieving porous structure. Compared to ASCs spreading along the surface of pores within scaffold, the dense mass of aggregated ASCs in PLGA/CS scaffold exhibited enhanced chondrogenic differentiation capacity, as determined by up-regulated GAGs and COL II expression, and greatly decreased COL I deposition during in vitro chondrogenesis. Furthermore, after 12 weeks of implantation, neo-cartilages generated by ASCs adhered on scaffold significantly presented fibrous matrix which was characterized by high levels of COL I deposition. However, neo-cartilage at 12 weeks post-implantation generated by PLGA/CS scaffold carrying ASC spheroids possessed similar high level of GAGs and COL II and low level of COL I as that in normal cartilage. The in vitro and in vivo results indicated the present strategy could not only promote chondrogenesis of ASCs, but also facilitate hyaline-like cartilage regeneration with reduced fibrous tissue formation which may attenuate cartilage degradation in future long-term follow-up. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. NANOCOVERING OF TITAN WITH SILICON AND MOLYBDENUM AS ACTIVATOR OF FORMATION AND REACTIONARY AGGLOMERATION OF FILTERS AND MEMBRANES

    Directory of Open Access Journals (Sweden)

    V. N. Kovalevski

    2014-01-01

    Full Text Available The technology of production of porous powder materials with frame structure on the basis of spherical particles of titan powder by means of applying on them technological coverings (Si + Mo + C with the thickness up to 2 mm is developed. Formation of powders with covering was carried out in the mold at pressure below yield point (up to 150 MPa.

  14. Effect of Cytokines on Osteoclast Formation and Bone Resorption during Mechanical Force Loading of the Periodontal Membrane

    Directory of Open Access Journals (Sweden)

    Hideki Kitaura

    2014-01-01

    Full Text Available Mechanical force loading exerts important effects on the skeleton by controlling bone mass and strength. Several in vivo experimental models evaluating the effects of mechanical loading on bone metabolism have been reported. Orthodontic tooth movement is a useful model for understanding the mechanism of bone remodeling induced by mechanical loading. In a mouse model of orthodontic tooth movement, TNF-α was expressed and osteoclasts appeared on the compressed side of the periodontal ligament. In TNF-receptor-deficient mice, there was less tooth movement and osteoclast numbers were lower than in wild-type mice. These results suggest that osteoclast formation and bone resorption caused by loading forces on the periodontal ligament depend on TNF-α. Several cytokines are expressed in the periodontal ligament during orthodontic tooth movement. Studies have found that inflammatory cytokines such as IL-12 and IFN-γ strongly inhibit osteoclast formation and tooth movement. Blocking macrophage colony-stimulating factor by using anti-c-Fms antibody also inhibited osteoclast formation and tooth movement. In this review we describe and discuss the effect of cytokines in the periodontal ligament on osteoclast formation and bone resorption during mechanical force loading.

  15. Midazolam inhibits the formation of amyloid fibrils and GM1 ganglioside-rich microdomains in presynaptic membranes through the gamma-aminobutyric acid A receptor.

    Science.gov (United States)

    Yamamoto, Naoki; Arima, Hajime; Sugiura, Takeshi; Hirate, Hiroyuki; Kusama, Nobuyoshi; Suzuki, Kenji; Sobue, Kazuya

    2015-02-20

    Recent studies have suggested that a positive correlation exists between surgical interventions performed under general anesthesia and the risk of developing Alzheimer's disease (AD) in the late postoperative period. It has been reported that amyloid β-protein (Αβ) fibrillogenesis, which is closely related to AD, is accelerated by exposure to anesthetics. However, the mechanisms underlying these effects remain uncertain. This study was designed to investigate whether the anesthetic midazolam affects Αβ fibrillogenesis, and if so, whether it acts through GM1 ganglioside (GM1) on the neuronal surface. Midazolam treatment decreased GM1 expression in the detergent-resistant membrane microdomains of neurons, and these effects were regulated by the gamma-aminobutyric acid-A receptor. Midazolam inhibited Αβ fibril formation from soluble Αβ on the neuronal surface. In addition, midazolam suppressed GM1-induced fibril formation in a cell-free system. Moreover, midazolam inhibited the formation of Αβ assemblies in synaptosomes isolated from aged mouse brains. These finding suggested that midazolam has direct and indirect inhibitory effects on Αβ fibrillogenesis.

  16. Spatiotemporal Pattern Formation in BioFluids I: Cell Shape Perturbants As Evidence of Spatially-Organised Membrane Flows

    CERN Document Server

    Lofthouse, J T

    2003-01-01

    I show the assumed Bilayer structure of cell membranes is Topologically falsified by known aminophospholipid dynamics in metabolically-active, Far from Equilibrium cells. The sensitivity of lipid and cytoplasmic flows to temperature, surfactants, viscosity and the gravity vector are used to suggest that rather than being random viscous fluids as currently assumed, both are actually spatially-organised by convective and shear driven mechanisms in vivo. I show how protein-lipid feedback provokes a Gestalt Shift in Cell Mechanics by demonstrating that the primary forces involved in shape changes are generated by bifurcations in fluid flow Topology, which induce affine deformations of the cytoskeletal lattice. The feedback model allows the transduction of Gravitational information into biological form, is universally applicable, and provides a rationale for Homeoviscous Adaptation, and the extensive lipid polymorphism observed in Nature.

  17. Fibrous capsule formation of the peritoneal catheter tip in ventriculoperitoneal shunt: Two case reports

    Directory of Open Access Journals (Sweden)

    Tomoaki Kano

    2014-01-01

    Full Text Available Background: A fibrous capsule formation of a peritoneal catheter tip has not previously been researched as a complication of ventriculoperitoneal (VP shunts. Case Description: Two adult patients who had undergone a VP shunt for communicative hydrocephalus following subarachnoid hemorrhage caused by a ruptured aneurysm have been identified with malfunction of the VP shunt system by mild disturbance of consciousness and gait disturbance or loss of appetite. Hydrocephalus was diagnosed by computed tomography and the obstruction of the peritoneal catheter was revealed by shuntgraphy. Laparoscopy was performed and the peritoneal catheter tips were obstructed by fibrous white capsules that covered them. One was a thin membranous capsule like a stocking with two small endoluminal granulomas of the peritoneal catheter, and other one was a fibrous glossy white capsule like a sock. These fibrous capsules were excised by laparoscopy forceps without the conversion to a new peritoneal catheter. Following the procedure, the shunt functioned normally. The pathological diagnoses were peritoneum with foreign body reaction or hyalinization of membranous tissue surrounded by fibrous tissue. Conclusion: These fibrous capsules might be formed by the peritoneal reaction to cerebrospinal fluid as a foreign material. As such, a periodic medical check should be scheduled since a fibrous capsule of the peritoneal catheter tip might be formed again.

  18. Giant vesicles from 72-membered macrocyclic archaeal phospholipid analogues: initiation of vesicle formation by molecular recognition between membrane components

    Science.gov (United States)

    Eguchi; Arakawa; Kakinuma; Rapp; Ghosh; Nakatani; Ourisson

    2000-09-15

    Stereochemically pure archeal acyclic bola-amphiphilic diphosphates 4 and 5, with the basic structure of the phospholipids found in Sulfolobus, have been synthesized for the first time. The self-assembly properties have been compared with those of the nearly identical 72-membered macrocyclic tetraether phosphates 3a and 3b, analogues of the major phospholipid components of Sulfolobus, Thermoplasma, and methanogenic Archea, which were also synthesized. Phase contrast and fluorescence microscopies have shown that the dipolar lipids 1 and 2 spontaneously formed vesicles. Whereas the macrocyclic dipolar phosphates 3 spontaneously formed vesicles (phase contrast and fluorescence microscopies), the bolaform phosphate 4 gave only a lamellar structure (synchrotron diffraction pattern: repeat distance of about 4.25 nm but with only a few layers). However, upon addition of the unphosphorylated precursors phytanol, phytol, or geranylgeraniol to the acyclic lipids 4 and 5, giant vesicles were rapidly formed. Addition of n-hexadecanol or cholesterol did not lead to vesicle formation. Therefore it was concluded that this vesicle formation occurs only when the added molecule is closely compatible with the constituents of the lipid layer and can be inserted into the double layer. A slight mismatch (cholesterol or n-hexadecanol/polyprenyl chains) is therefore enough to block the insertion process presumably required for vesicle formation.

  19. Modulation of Membrane Influx and Efflux in Escherichia coli Sequence Type 131 Has an Impact on Bacterial Motility, Biofilm Formation, and Virulence in a Caenorhabditis elegans Model

    Science.gov (United States)

    Pantel, Alix; Dunyach-Remy, Catherine; Ngba Essebe, Christelle; Mesureur, Jennifer; Sotto, Albert; Nicolas-Chanoine, Marie-Hélène

    2016-01-01

    Energy-dependent efflux overexpression and altered outer membrane permeability (influx) can promote multidrug resistance (MDR). The present study clarifies the regulatory pathways that control membrane permeability in the pandemic clone Escherichia coli sequence type 131 (ST131) and evaluates the impact of efflux and influx modulations on biofilm formation, motility, and virulence in the Caenorhabditis elegans model. Mutants of two uropathogenic E. coli (UPEC) strains, MECB5 (ST131; H30-Rx) and CFT073 (ST73), as well as a fecal strain, S250 (ST131; H22), were in vitro selected using continuous subculture in subinhibitory concentrations of ertapenem (ETP), chloramphenicol (CMP), and cefoxitin (FOX). Mutations in genes known to control permeability were shown for the two UPEC strains: MECB5-FOX (deletion of 127 bp in marR; deletion of 1 bp and insertion of an IS1 element in acrR) and CFT073-CMP (a 1-bp deletion causing a premature stop in marR). We also demonstrated that efflux phenotypes in the mutants selected with CMP and FOX were related to the AcrAB-TolC pump, but also to other efflux systems. Alteration of membrane permeability, caused by underexpression of the two major porins, OmpF and OmpC, was shown in MECB5-ETP and mutants selected with FOX. Lastly, our findings suggest that efflux pump-overproducing isolates (CMP mutants) pose a serious threat in terms of virulence (significant reduction in worm median survival) and host colonization. Lack of porins (ETP and FOX mutants) led to a high level of antibiotic resistance in an H30-Rx subclone. Nevertheless, this adaptation created a physiological disadvantage (decreased motility and ability to form biofilm) associated with a low potential for virulence. PMID:26926643

  20. Tumor fusocelular hialinizante con rosetas gigantes: Reporte de un caso Hyalinizing spindle cell tumor with giant rosettes: Case report

    Directory of Open Access Journals (Sweden)

    Ernesto García Ayala

    2010-12-01

    Full Text Available Introducción: El tumor fusocelular hialinizante con rosetas gigantes es una neoplasia constituida por dos componentes histológicos, uno celular con elementos fusiformes, y el segundo representado por islas bien delimitadas casi acelulares, llenas de material hialino, rodeadas de células redondas u ovales, las cuales muestran un perfil inmunohistoquímico inusual, e histogénesis incierta. Objetivo: Instruir a los patólogos y clínicos sobre este tumor, su forma de presentación y diagnósticos diferenciales. Metodología y resultados: Se presenta el caso de una mujer de 42 años con masa ubicada en región inguinal, de crecimiento progresivo (1 año, que se reseca quirúrgicamente anatomía patológica informó un tumor fusocelular hialinizante con rosetas gigantes, según hallazgos morfológicos e inmuno histoquímicos, en correlación con su localización y cuadro clínico. Conclusión: Se hace necesario ampliar el conocimiento sobre esta entidad y de esta forma obtener una adecuada evaluación de sus criterios pronósticos histológicos, comportamiento clínico y tratamiento. Salud UIS 2010; 42: 282-286Introduction: The hyalinizing spindle cell tumor with giant rosettes is a neoplasia characterized by both histologic components, one of which is cellular, with spindle-shaped elements and the second represented by well defined almost acellular islands filled with hyaline material surrounded by round to oval cells, which shows an unusual immunohistochemical profile and uncertain histogenesis. Objective: Educate pathologists and clinicians about this tumor, its presentation and differential diagnosis. Methods and results: A case of a 42 year old woman with a mass located in the inguinal region, with progressive growth (1 year, surgically resected and histopathology reported as Hyalinizing spindle cell tumor with giant rosettes according to morphological, immunohistochemical findings correlates with its location and clinical. Conclusion: It is

  1. Choroidal Neovascular Membrane Formation and Retinochoroidopathy in a Patient with Systemic Langerhans Cell Histiocytosis: A Case Report and Review of the Literature

    Directory of Open Access Journals (Sweden)

    Aristomenis Thanos

    2012-04-01

    Full Text Available We report a case of bilateral atrophic retinochoroidopathy with choroidal neovascular membrane (CNVM formation in a patient with systemic Langerhans cell histiocytosis (LCH. A 35-year-old female, diagnosed with LCH at the age of 3, experienced an episode of acute vision loss in her right eye. Visual acuity was counting fingers. Dilated fundus exam and fluorescein angiography revealed the presence of CNVM along with bilateral widespread areas of chorioretinal atrophy. The patient underwent removal of CNVM with excellent postoperative visual acuity (20/25; however, indolent progression of her disease led to gradual deterioration of visual acuity (20/80 in the right eye and 20/320 in the left. This case shows that in contrast to previous reports, intraocular involvement of LCH does not need to be dramatic and clinically evident but it can acquire a chronic degenerative form. This report aims to raise awareness among ophthalmologists concerning the potential intraocular sequelae of LCH.

  2. Use of mutated self-cleaving 2A peptides as a molecular rheostat to direct simultaneous formation of membrane and secreted anti-HIV immunoglobulins.

    Science.gov (United States)

    Yu, Kenneth K; Aguilar, Kiefer; Tsai, Jonathan; Galimidi, Rachel; Gnanapragasam, Priyanthi; Yang, Lili; Baltimore, David

    2012-01-01

    In nature, B cells produce surface immunoglobulin and secreted antibody from the same immunoglobulin gene via alternative splicing of the pre-messenger RNA. Here we present a novel system for genetically programming B cells to direct the simultaneous formation of membrane-bound and secreted immunoglobulins that we term a "Molecular Rheostat", based on the use of mutated "self-cleaving" 2A peptides. The Molecular Rheostat is designed so that the ratio of secreted to membrane-bound immunoglobulins can be controlled by selecting appropriate mutations in the 2A peptide. Lentiviral transgenesis of Molecular Rheostat constructs into B cell lines enables the simultaneous expression of functional b12-based IgM-like BCRs that signal to the cells and mediate the secretion of b12 IgG broadly neutralizing antibodies that can bind and neutralize HIV-1 pseudovirus. We show that these b12-based Molecular Rheostat constructs promote the maturation of EU12 B cells in an in vitro model of B lymphopoiesis. The Molecular Rheostat offers a novel tool for genetically manipulating B cell specificity for B-cell based gene therapy.

  3. Effects of inorganic ions on morphology of octacalcium phosphate grown on cation selective membrane at physiological temperature and pH in relation to enamel formation

    Science.gov (United States)

    Iijima, Mayumi; Moriwaki, Yutaka

    1989-05-01

    The crystal growth of octacalcium phosphate (OCP) is of particular interest, since there is a possibility that OCP is formed in the early stage of tooth enamel formation. In this study, the effects of CO2-3, Mg2+ and F-ions on the morphology of OCP were investigated in a membrane system, where a cation selective membrane was used to simulate amelogenesis. Reactions were carried out at pH 6.3, 6.5 and 6.8 for 3 days at 37°C. In most cases, these ions suppressed the crystal growth in the c-axis direction of OCP, particularly when they coexisted. The morphology of OCP crystal changed from ribbon-like to flake-like, depending on the inhibitory activity. The inhibitory activity, particularly that of F - ion, was suppressed at pH lower than pH 6.8. Antagonistic effect of Mg2+ and F-ion was observed at pH 6.5. In the case of F - ion, OCP crystals showed a unique pattern, which suggests hydrolysis of OCP and subsequent growth of apatite. These findings indicate that inorganic ions, particularly F - ion, influence the growth of OCP. Although CO2-3, Mg2+andF-ions coexisted, extended growth in the c-axis direction of OCP took place at pH 6.0.

  4. The bacterial cytoskeleton and its putative role in membrane vesicle formation observed in a Gram-positive bacterium producing starch-degrading enzymes.

    Science.gov (United States)

    Mayer, Frank; Gottschalk, Gerhard

    2003-01-01

    Bacteria may possess various kinds of cytoskeleton. In general, bacterial cytoskeletons may play a role in the control and preservation of the cell shape. Such functions become especially evident when the bacteria do not possess a true wall and are nevertheless elongated (e.g. Mycoplasma spp.) or under extreme cultivation conditions whereby loss of the entire bacterial cell wall takes place. Bacterial cytoskeletons may control and preserve the cell shape only if a number of preconditions are fulfilled. They should be present not only transiently, but permanently, they should be located as a lining close to the inner face of the cytoplasmic membrane, enclosing the entire cytoplasm, and they should comprise structural elements (fibrils) crossing the inner volume of the cell in order to provide the necessary stability for the lining. Complete loss of the cell wall layers had earlier been observed to occur during extensive production of bacterial starch-degrading enzymes in an optimized fermentation process by a Gram-positive bacterium. Even under these conditions, the cells had maintained their elongated shape and full viability. Which of the various kinds of bacterial cytoskeleton might have been responsible for shape preservation? Only one of them, the primary or basic cytoskeleton turns out to fulfil the necessary preconditions listed above. Its structural features now provided a first insight into a possible mechanism of formation of membrane blebs and vesicles as observed in the Gram-positive eubacterium Thermoanaerobacterium thermosulfurogenes EM1, and the putative role of the cytoskeletal web in this process.

  5. Use of mutated self-cleaving 2A peptides as a molecular rheostat to direct simultaneous formation of membrane and secreted anti-HIV immunoglobulins.

    Directory of Open Access Journals (Sweden)

    Kenneth K Yu

    Full Text Available In nature, B cells produce surface immunoglobulin and secreted antibody from the same immunoglobulin gene via alternative splicing of the pre-messenger RNA. Here we present a novel system for genetically programming B cells to direct the simultaneous formation of membrane-bound and secreted immunoglobulins that we term a "Molecular Rheostat", based on the use of mutated "self-cleaving" 2A peptides. The Molecular Rheostat is designed so that the ratio of secreted to membrane-bound immunoglobulins can be controlled by selecting appropriate mutations in the 2A peptide. Lentiviral transgenesis of Molecular Rheostat constructs into B cell lines enables the simultaneous expression of functional b12-based IgM-like BCRs that signal to the cells and mediate the secretion of b12 IgG broadly neutralizing antibodies that can bind and neutralize HIV-1 pseudovirus. We show that these b12-based Molecular Rheostat constructs promote the maturation of EU12 B cells in an in vitro model of B lymphopoiesis. The Molecular Rheostat offers a novel tool for genetically manipulating B cell specificity for B-cell based gene therapy.

  6. Formation of inverse Chladni patterns at microscale by acoustic streaming on a silicon membrane immersed in a liquid

    Science.gov (United States)

    Poulain, Cedric; Vuillermet, Gael; Casset, Fabrice

    2015-11-01

    High frequency acoustics (in the MHz range) is known to be very efficient to handle micro particles or living cells in microfluidics by taking advantage of the acoustic radiation force. Here, we will show that low frequency (~ 50kHz) together with use ultra thin silicon plate can give rise to a micro streaming that enables to move particles at will. Indeed, by means of silicon membranes excited in the low ultrasound range, we show that it is possible to form inverse two-dimensional Chladni patterns of micro-beads in liquid. Unlike the well-known effect in a gaseous environment at macroscale, where gravity effects are generally dominant, leading particles towards the nodal regions of displacement, we will show that the micro scale streaming in the vicinity of the plate tends to gather particles in antinodal regions. Moreover, a symmetry breaking effect together with the streaming can trigger a whole rotation of the beads in the fluidic cavity. We demonstrate that it is possible to make the patterns rotate at a well defined angular velocity where beads actually jump from one acoustic trap to another.

  7. Palladium Recovery in a H2-Based Membrane Biofilm Reactor: Formation of Pd(0) Nanoparticles through Enzymatic and Autocatalytic Reductions.

    Science.gov (United States)

    Zhou, Chen; Ontiveros-Valencia, Aura; Wang, Zhaocheng; Maldonado, Juan; Zhao, He-Ping; Krajmalnik-Brown, Rosa; Rittmann, Bruce E

    2016-03-01

    Recovering palladium (Pd) from waste streams opens up the possibility of augmenting the supply of this important catalyst. We evaluated Pd reduction and recovery as a novel application of a H2-based membrane biofilm reactor (MBfR). At steady states, over 99% of the input soluble Pd(II) was reduced through concomitant enzymatic and autocatalytic processes at acidic or near neutral pHs. Nanoparticulate Pd(0), at an average crystallite size of 10 nm, was recovered with minimal leaching and heterogeneously associated with microbial cells and extracellular polymeric substances in the biofilm. The dominant phylotypes potentially responsible for Pd(II) reduction at circumneutral pH were denitrifying β-proteobacteria mainly consisting of the family Rhodocyclaceae. Though greatly shifted by acidic pH, the biofilm microbial community largely bounced back when the pH was returned to 7 within 2 weeks. These discoveries infer that the biofilm was capable of rapid adaptive evolution to stressed environmental change, and facilitated Pd recovery in versatile ways. This study demonstrates the promise of effective microbially driven Pd recovery in a single MBfR system that could be applied for the treatment of the waste streams, and it documents the role of biofilms in this reduction and recovery process.

  8. From biological membranes to biomimetic model membranes

    Directory of Open Access Journals (Sweden)

    Eeman, M.

    2010-01-01

    Full Text Available Biological membranes play an essential role in the cellular protection as well as in the control and the transport of nutrients. Many mechanisms such as molecular recognition, enzymatic catalysis, cellular adhesion and membrane fusion take place into the biological membranes. In 1972, Singer et al. provided a membrane model, called fluid mosaic model, in which each leaflet of the bilayer is formed by a homogeneous environment of lipids in a fluid state including globular assembling of proteins and glycoproteins. Since its conception in 1972, many developments were brought to this model in terms of composition and molecular organization. The main development of the fluid mosaic model was made by Simons et al. (1997 and Brown et al. (1997 who suggested that membrane lipids are organized into lateral microdomains (or lipid rafts with a specific composition and a molecular dynamic that are different to the composition and the dynamic of the surrounding liquid crystalline phase. The discovery of a phase separation in the plane of the membrane has induced an explosion in the research efforts related to the biology of cell membranes but also in the development of new technologies for the study of these biological systems. Due to the high complexity of biological membranes and in order to investigate the biological processes that occur on the membrane surface or within the membrane lipid bilayer, a large number of studies are performed using biomimicking model membranes. This paper aims at revisiting the fundamental properties of biological membranes in terms of membrane composition, membrane dynamic and molecular organization, as well as at describing the most common biomimicking models that are frequently used for investigating biological processes such as membrane fusion, membrane trafficking, pore formation as well as membrane interactions at a molecular level.

  9. Lineage plasticity and cell biology of fibrocartilage and hyaline cartilage: Its significance in cartilage repair and replacement

    Energy Technology Data Exchange (ETDEWEB)

    Freemont, Anthony J. [Regenerative Medicine Research Group, University of Manchester, England (United Kingdom)]. E-mail: Tony.freemont@man.ac.uk; Hoyland, Judith [Regenerative Medicine Research Group, University of Manchester, England (United Kingdom)

    2006-01-15

    Cartilage repair is a major goal of modern tissue engineering. To produce novel engineered implants requires a knowledge of the basic biology of the tissues that are to be replaced or reproduced. Hyaline articular cartilage and meniscal fibrocartilage are two tissues that have excited attention because of the frequency with which they are damaged. A basic strategy is to re-engineer these tissues ex vivo by stimulating stem cells to differentiate into the cells of the mature tissue capable of producing an intact functional matrix. In this brief review, the sources of cells for tissue engineering cartilage and the culture conditions that have promoted differentiation are discussed within the context of natural cartilage repair. In particular, the role of cell density, cytokines, load, matrices and oxygen tension are discussed.

  10. Hyalinizing cholecystitis with features of immunoglobulin G4-related disease-coincidence or an unrecognized association? A case report.

    Science.gov (United States)

    Gupta, Rajib K; Patton, Kurt T

    2015-04-01

    Hyalinizing cholecystitis (HC) is a recently described rare subtype of chronic cholecystitis characterized by dense, paucicellular collagenous transmural fibrosis, which usually replaces the mucosa and muscularis propria. Immunoglobulin (Ig)G4-associated cholecystitis is also a newly described cholecystitis variant characterized by transmural or extramural lymphoplasmacytic inflammation, lymphoid follicles, storiform fibrosis, phlebitis, and increased tissue IgG4-positive plasma cells. We describe a case of cholecystitis in an elderly white man who harbored features of both HC and IgG4-associated cholecystitis. In retrospect, the patient also had a significantly elevated serum IgG4 level. To the best of our knowledge, an association between HC and IgG4-related disease has not been previously described in the literature. Although not entirely conclusive, our observations raise the possibility that some cases of HC represent the end stage of IgG4-related disease.

  11. Use of Interim Scaffolding and Neotissue Development to Produce a Scaffold-Free Living Hyaline Cartilage Graft.

    Science.gov (United States)

    Lau, Ting Ting; Leong, Wenyan; Peck, Yvonne; Su, Kai; Wang, Dong-An

    2015-01-01

    The fabrication of three-dimensional (3D) constructs relies heavily on the use of biomaterial-based scaffolds. These are required as mechanical supports as well as to translate two-dimensional cultures to 3D cultures for clinical applications. Regardless of the choice of scaffold, timely degradation of scaffolds is difficult to achieve and undegraded scaffold material can lead to interference in further tissue development or morphogenesis. In cartilage tissue engineering, hydrogel is the highly preferred scaffold material as it shares many similar characteristics with native cartilaginous matrix. Hence, we employed gelatin microspheres as porogens to create a microcavitary alginate hydrogel as an interim scaffold to facilitate initial chondrocyte 3D culture and to establish a final scaffold-free living hyaline cartilaginous graft (LhCG) for cartilage tissue engineering.

  12. Droplet and slug formation in polymer electrolyte membrane fuel cell flow channels: The role of interfacial forces

    Science.gov (United States)

    Colosqui, Carlos E.; Cheah, May J.; Kevrekidis, Ioannis G.; Benziger, Jay B.

    A microfluidic device is employed to emulate water droplet emergence from a porous electrode and slug formation in the gas flow channel of a PEM fuel cell. Liquid water emerges from a 50 μm pore forming a droplet; the droplet grows to span the entire cross-section of a microchannel and transitions into a slug which detaches and is swept downstream. Droplet growth, slug formation, detachment, and motion are analyzed using high-speed video images and pressure-time traces. Slug volume is controlled primarily by channel geometry, interfacial forces, and gravity. As water slugs move downstream, they leave residual micro-droplets that act as nucleation sites for the next droplet-to-slug transition. Residual liquid in the form of micro-droplets results in a significant decrease in slug volume between the very first slug formed in an initially dry channel and the ultimate "steady-state" slug. A physics-based model is presented to predict slug volumes and pressure drops for slug detachment and motion.

  13. Production of hyaline-like cartilage by bone marrow mesenchymal stem cells in a self-assembly model.

    Science.gov (United States)

    Elder, Steven H; Cooley, Avery J; Borazjani, Ali; Sowell, Brittany L; To, Harrison; Tran, Scott C

    2009-10-01

    A scaffoldless or self-assembly approach to cartilage tissue engineering has been used to produce hyaline cartilage from bone marrow-derived mesenchymal stem cells (bMSCs), but the mechanical properties of such engineered cartilage and the effects the transforming growth factor (TGF) isoform have not been fully explored. This study employs a cell culture insert model to produce tissue-engineered cartilage using bMSCs. Neonatal pig bMSCs were isolated by plastic adherence and expanded in monolayer before being seeded into porous transwell inserts and cultured for 4 or 8 weeks in defined chondrogenic media containing either TGF-beta1 or TGF-beta3. Following biomechanical evaluation in confined compression, colorimetric dimethyl methylene blue and Sircol dye-binding assays were used to analyze glycosaminoglycan (GAG) and collagen contents, respectively. Histological sections were stained with toluidine blue for proteoglycans and with picrosirius red to reveal collagen orientation, and immunostained for detection of collagen types I and II. Neocartilage increased in thickness, collagen, and GAG content between 4 and 8 weeks. Proteoglycan concentration increased with depth from the top surface. The tissue contained much more collagen type II than type I, and there was a consistent pattern of collagen alignment. TGF-beta1-treated and TGF-beta3-treated constructs were similar at 4 weeks, but 8-week TGF-beta1 constructs had a higher aggregate modulus and GAG content compared to TGF-beta3. These results demonstrate that bMSCs can generate functional hyaline-like cartilage through a self-assembling process.

  14. Release of transgenic progranulin from a living hyaline cartilage graft model: An in vitro evaluation on anti-inflammation.

    Science.gov (United States)

    Lau, Ting Ting; Zhang, Feng; Tang, Wei; Wang, Dong-An

    2016-12-01

    Osteoarthritis (OA) is a prevalent condition that compromises and even jeopardizes the life quality of millions of people. Common symptoms in OA includes joint stiffness and soreness, and they are often associated with inflammations to various extend. Due to the avascular and aneural nature of articular hyaline cartilage, it has limited self-repair capabilities; especially under inflammatory conditions, damages inflicted on cartilage are often irreversible. Hence, treatment approaches focus on anti-inflammation or articular cartilage replacement. In this study, an engineered, dual-functional living hyaline cartilage graft (LhCG), capable of releasing transgenic anti-inflammatory cytokine-progranulin (PGRN) is developed and envisioned to simultaneously fulfil both requirements. The therapeutic functionality of PGRN releasing LhCG is evaluated by co-culturing the constructs with tumor necrosis factor-alpha (TNFα) secreting THP-1 cells to simulate the inflammatory condition in arthritis. Non-transgenic LhCG constructs and non-coculture sample groups were set up as controls. Gene expression and ECM composition changes across samples were assessed to understand the effects of PGRN as well as inflammatory environment on the cartilage graft. Collectively, the results in this study suggest that in situ release of transgenic recombinant PGRN protects LhCG from induced inflammation in vitro; contrastively, in the absence of PGRN, cartilage grafts are at risk of being degraded and mineralized under exposure to TNFα signaling. This shows that cartilage graft itself can be at risk of degradation or calcification when implanted in arthritic microenvironment. Hence, the inflammatory microenvironment has to be considered in cartilage replacement therapy to increase chances of successful joint mobility restoration. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2968-2977, 2016. © 2016 Wiley Periodicals, Inc.

  15. Conversion of membrane lipid acyl groups to triacylglycerol and formation of lipid bodies upon nitrogen starvation in biofuel green algae Chlorella UTEX29.

    Science.gov (United States)

    Goncalves, Elton C; Johnson, Jodie V; Rathinasabapathi, Bala

    2013-11-01

    Algal lipids are ideal biofuel sources. Our objective was to determine the contributors to triacylglycerol (TAG) accumulation and lipid body formation in Chlorella UTEX29 under nitrogen (N) deprivation. A fivefold increase in intracellular lipids following N starvation for 24 h confirmed the oleaginous characteristics of UTEX29. Ultrastructural studies revealed increased number of lipid bodies and decreased starch granules in N-starved cells compared to N-replete cells. Lipid bodies were observed as early as 3 h after N removal and plastids collapsed after 48 h of stress. Moreover, the identification of intracellular pyrenoids and differences in the expected nutritional requirements for Chlorella protothecoides (as UTEX29 is currently classified) led us to conduct a phylogenetic study using 18S and actin cDNA sequences. This indicated UTEX29 to be more phylogenetically related to Chlorella vulgaris. To investigate the fate of different lipids after N starvation, radiolabeling using ¹⁴C-acetate was used. A significant decrease in ¹⁴C-galactolipids and phospholipids matched the increase in ¹⁴C-TAG starting at 3 h of N starvation, consistent with acyl groups from structural lipids as sources for TAG under N starvation. These results have important implications for the identification of key steps controlling oil accumulation in N-starved biofuel algae and demonstrate membrane recycling during lipid body formation.

  16. Molybdenum-containing membrane-bound formate dehydrogenase isolated from Citrobacter sp. S-77 having high stability against oxygen, pH, and temperature.

    Science.gov (United States)

    Nguyen, Nga T; Yatabe, Takeshi; Yoon, Ki-Seok; Ogo, Seiji

    2014-10-01

    Membrane-bound formate dehydrogenase (FDH) was purified to homogeneity from a facultative anaerobic bacterium Citrobacter sp. S-77. The FDH from Citrobacter sp. S-77 (FDHS77) was a monomer with molecular mass of approximately 150 kDa. On SDS-PAGE, the purified FDHS77 showed as three different protein bands with molecular mass of approximately 95, 87, and 32 kDa, respectively. Based on the N-terminal amino acid sequence analysis, the sequence alignments observed for the 87 kDa protein band were identical to that of the large subunit of 95 kDa, indicating that the purified FDHS77 consisted of two subunits; a 95 kDa large subunit and a 32 kDa small subunit. The purified FDHS77 in this purification did not contain a heme b subunit, but the FDHS77 showed significant activity for formate oxidation, determined by the Vmax of 30.4 U/mg using benzyl viologen as an electron acceptor. The EPR and ICP-MS spectra indicate that the FDHS77 is a molybdenum-containing enzyme, displaying a remarkable O2-stability along with thermostability and pH resistance. This is the first report of the purification and characterization of a FDH from Citrobacter species.

  17. Lgr4 and Lgr5 drive the formation of long actin-rich cytoneme-like membrane protrusions

    Science.gov (United States)

    Snyder, Joshua C.; Rochelle, Lauren K.; Marion, Sébastien; Lyerly, H. Kim; Barak, Larry S.; Caron, Marc G.

    2015-01-01

    ABSTRACT Embryonic development and adult tissue homeostasis require precise information exchange between cells and their microenvironment to coordinate cell behavior. A specialized class of ultra-long actin-rich filopodia, termed cytonemes, provides one mechanism for this spatiotemporal regulation of extracellular cues. We provide here a mechanism whereby the stem-cell marker Lgr5, and its family member Lgr4, promote the formation of cytonemes. Lgr4- and Lgr5-induced cytonemes exceed lengths of 80 µm, are generated through stabilization of nascent filopodia from an underlying lamellipodial-like network and functionally provide a pipeline for the transit of signaling effectors. As proof-of-principle, we demonstrate that Lgr5-induced cytonemes act as conduits for cell signaling by demonstrating that the actin motor and filopodial cargo carrier protein myosin X (Myo10) and the G-protein-coupled receptor (GPCR) signaling effector β-arrestin-2 (Arrb2) transit into cytonemes. This work delineates a biological function for Lgr4 and Lgr5 and provides the rationale to fully investigate Lgr4 and Lgr5 function and cytonemes in mammalian stem cell and cancer stem cell behavior. PMID:25653388

  18. Analysis of liquid water formation in polymer electrolyte membrane (PEM) fuel cell flow fields with a dry cathode supply

    Science.gov (United States)

    Gößling, Sönke; Klages, Merle; Haußmann, Jan; Beckhaus, Peter; Messerschmidt, Matthias; Arlt, Tobias; Kardjilov, Nikolay; Manke, Ingo; Scholta, Joachim; Heinzel, Angelika

    2016-02-01

    PEM fuel cells can be operated within a wide range of different operating conditions. In this paper, the special case of operating a PEM fuel cell with a dry cathode supply and without external humidification of the cathode, is considered. A deeper understanding of the water management in the cells is essential for choosing the optimal operation strategy for a specific system. In this study a theoretical model is presented which aims to predict the location in the flow field at which liquid water forms at the cathode. It is validated with neutron images of a PEM fuel cell visualizing the locations at which liquid water forms in the fuel cell flow field channels. It is shown that the inclusion of the GDL diffusion resistance in the model is essential to describe the liquid water formation process inside the fuel cell. Good agreement of model predictions and measurement results has been achieved. While the model has been developed and validated especially for the operation with a dry cathode supply, the model is also applicable to fuel cells with a humidified cathode stream.

  19. Neuronal filopodium formation induced by the membrane glycoprotein M6a (Gpm6a) is facilitated by coronin-1a, Rac1, and p21-activated kinase 1 (Pak1).

    Science.gov (United States)

    Alvarez Juliá, Anabel; Frasch, Alberto C; Fuchsova, Beata

    2016-04-01

    Stress-responsive neuronal membrane glycoprotein M6a (Gpm6a) functions in neurite extension, filopodium and spine formation and synaptogenesis. The mechanisms of Gpm6a action in these processes are incompletely understood. Previously, we identified the actin regulator coronin-1a (Coro1a) as a putative Gpm6a interacting partner. Here, we used co-immunoprecipitation assays with the anti-Coro1a antibody to show that Coro1a associates with Gpm6a in rat hippocampal neurons. By immunofluorescence microscopy, we demonstrated that in hippocampal neurons Coro1a localizes in F-actin-enriched regions and some of Coro1a spots co-localize with Gpm6a labeling. Notably, the over-expression of a dominant-negative form of Coro1a as well as its down-regulation by siRNA interfered with Gpm6a-induced filopodium formation. Coro1a is known to regulate the plasma membrane translocation and activation of small GTPase Rac1. We show that Coro1a co-immunoprecipitates with Rac1 together with Gpm6a. Pharmacological inhibition of Rac1 resulted in a significant decrease in filopodium formation by Gpm6a. The same was observed upon the co-expression of Gpm6a with the inactive GDP-bound form of Rac1. In this case, the elevated membrane recruitment of GDP-bound Rac1 was detected as well. Moreover, the kinase activity of the p21-activated kinase 1 (Pak1), a main downstream effector of Rac1 that acts downstream of Coro1a, was required for Gpm6a-induced filopodium formation. Taken together, our results provide evidence that a signaling pathway including Coro1a, Rac1, and Pak1 facilitates Gpm6a-induced filopodium formation. Formation of filopodia by membrane glycoprotein M6a (Gpm6a) requires actin regulator coronin-1a (Coro1a), known to regulate plasma membrane localization and activation of Rac1 and its downstream effector Pak1. Coro1a associates with Gpm6a. Blockage of Coro1a, Rac1, or Pak1 interferes with Gpm6a-induced filopodium formation. Moreover, Gpm6a facilitates Rac1 membrane recruitment

  20. Latent membrane protein 1 of Epstein-Barr virus sensitizes cancer cells to cisplatin by enhancing NF-κB p50 homodimer formation and downregulating NAPA expression.

    Science.gov (United States)

    Wu, Zchong-Zcho; Chow, Kai-Ping N; Kuo, Tzu-Ching; Chang, Yu-Sun; Chao, Chuck C-K

    2011-12-15

    Expression of the oncogenic latent membrane protein 1 (LMP1) of Epstein-Barr virus is involved in the pathogenesis of nasopharyngeal carcinoma (NPC) and lymphoma. In previous studies, we found that expression of LMP1 was sufficient to transform BALB/c-3T3 cells. In contrast, other studies have shown that LMP1 induces apoptosis in a NF-κB-dependent manner and also inhibits the growth of tumors in mice, thereby indicating that LMP1 may produce various biological effects depending on the biological and cellular context. Still, the mechanism underlying the pro-apoptotic activity of LMP1 remains unclear. In the present study, we found that LMP1 inhibits the expression of NAPA, an endoplasmic reticulum SNARE protein that possesses anti-apoptotic properties against the DNA-damaging drug cisplatin. Accordingly, LMP1-transformed BALB/c-3T3 cells were sensitized to cisplatin-induced apoptosis, whereas no sensitization effect was noted following treatment with the mitotic spindle-damaging drugs vincristine and taxol. Knockdown of LMP1 with antisense oligonucleotides restored NAPA protein level and rendered the cells resistant to cisplatin. Similarly, overexpression of NAPA reduced the effect of LMP1 and induced resistance to cisplatin. LMP1 was shown to upregulate the NF-κB subunit p50, leading to formation of p50 homodimers on the NAPA promoter. These findings suggest that the viral protein LMP1 may sensitize cancer cells to cisplatin chemotherapy by downregulating NAPA and by enhancing the formation of p50 homodimers which in turn inhibit the expression of NF-κB regulated anti-apoptotic genes. These findings provide an explanatory mechanism for the pro-apoptotic activity of LMP1 as well as new therapeutic targets to control tumor growth.

  1. Parallel artificial liquid membrane extraction

    DEFF Research Database (Denmark)

    Gjelstad, Astrid; Rasmussen, Knut Einar; Parmer, Marthe Petrine

    2013-01-01

    This paper reports development of a new approach towards analytical liquid-liquid-liquid membrane extraction termed parallel artificial liquid membrane extraction. A donor plate and acceptor plate create a sandwich, in which each sample (human plasma) and acceptor solution is separated by an arti...... by an artificial liquid membrane. Parallel artificial liquid membrane extraction is a modification of hollow-fiber liquid-phase microextraction, where the hollow fibers are replaced by flat membranes in a 96-well plate format....

  2. MRI of the hyaline knee joint cartilage. Animal experimental and clinical studies; MRT des hyalinen Kniegelenkknorpels. Tierexperimentelle und klinische Untersuchungen

    Energy Technology Data Exchange (ETDEWEB)

    Adam, G. [Technische Hochschule Aachen (Germany). Klinik fuer Radiologische Diagnostik; Prescher, A. [Technische Hochschule Aachen (Germany). Inst. fuer Anatomie; Nolte-Ernsting, C. [Technische Hochschule Aachen (Germany). Klinik fuer Radiologische Diagnostik; Buehne, M. [Technische Hochschule Aachen (Germany). Klinik fuer Radiologische Diagnostik; Scherer, K. [Technische Hochschule Aachen (Germany). Inst. fuer Versuchstierkunde; Kuepper, W. [Technische Hochschule Aachen (Germany). Inst. fuer Versuchstierkunde; Guenther, R.W. [Technische Hochschule Aachen (Germany). Klinik fuer Radiologische Diagnostik

    1994-02-01

    The value of MR imaging for the detection of hyaline cartilage lesions using 2-D spin-echo and 3-D gradient-echo imaging was evaluated in an animal experiment in 10 dogs and in a clinical study in 30 patients. MR imaging findings were compared with histopathological and arthroscopy findings, respectively. Using MRI neither grade I nor grade II hyaline cartilage lesions were detectable. In the animal experiments 77% of grade III lesions and all the grade IV lesions were seen. However, in the clinical study only about the half of grade III and IV lesions were detected. 3-D gradient-echo MR imaging was superior to 2-D spin-echo imaging (p<0.001), while 3-D FLASH and 3-D FISP did not differ significantly in the detection rate (p<0.34). 3-D gradient-echo MR imaging seems to be the best method for the delineation of high grade cartilage lesions. However, early stages of cartilage degeneration are invisible even with this imaging modality. (orig.) [Deutsch] Die Wertigkeit der MRT in der Erfassung von Knorpellaesionen mit 2-D-Spin-Echo- und 3-D-Grafienten-Echo-Sequenzen wurde in einer tierexperimentellen Untersuchung an 10 Hunden sowie in einer klinischen Studie an 30 Patienten ueberprueft. Die kernspintomographischen Ergebnisse wurden mit dem pathologisch-anatomischen Befund bzw. der Arthroskopie verglichen. MR-tomographisch konnten weder Grad-I- noch Grad-II-Knorpellaesionen erfasst werden. Die Erkennbarkeitsrate der Grad-III- und -IV-Laesionen lag fuer die tierexperimentellen Untersuchungen bei 77 bzw. 100%, waehrend klinisch nur etwa 50% dieser Veraenderungen erkannt werden konnten. Dabei waren die 3-D-Gradienten-Echo-Sequenzen den 2-D-Spin-Echo-Sequenzen signifikant ueberlegen (p<0,001), waehrend sich die 3-D-Gradienten-Echo-Sequenzen FISP und FLASH nicht voneinander unterschieden (p<0,34). Derzeit muessen die 3-D-Gradienten-Echo-Sequenzen als die beste Methode zur Erfassung hoehergradiger Knorpellaesionen angesehen werden. Fruehe Stadien der Knorpelschaedigung sind

  3. Investigations into the visualisation of osseous and hyaline cartilaginous surface structures of the femural head using X-ray computed tomography. Untersuchung der Visualisierbarkeit knoecherner und hyalin knorpeliger Oberflaechenstrukturen des caput femoris mit Roentgen-Computertomographie

    Energy Technology Data Exchange (ETDEWEB)

    Laemmermann, G.

    1989-03-06

    This study investigates into the extent to which fine osseous structures in the head of the femur and hyaline cartilaginous surfaces of the hip joint are accessible to X-ray computed tomography as a method of diagnosis. At first, a true model of the femural head (post-mortem preparation embedded in methylacrylate) was tomographed to compare the sectional displays thus obtained with hard-microtome sections of similar thickness made at the same levels. This permitted preliminary evaluations to be carried out and confirmed that those structures can be visualised by high-resolution CT (1 mm sections). Methods using high-resolution sectional imaging have a role in examinations of congruence in the the hip joint. Particularly useful here are three-dimensional displays of osseous and cartilaginous surfaces of the joint parts examined. Further research is needed until a more refined method of reconstruction can be made available, the usefulness of which in actual practice will depend on the degree of geometrical congruence achieved between a patient's joint and its display on the screen. (orig./GDG).

  4. Subchondral chitosan/blood implant-guided bone plate resorption and woven bone repair is coupled to hyaline cartilage regeneration from microdrill holes in aged rabbit knees.

    Science.gov (United States)

    Guzmán-Morales, J; Lafantaisie-Favreau, C-H; Chen, G; Hoemann, C D

    2014-02-01

    Little is known of how to routinely elicit hyaline cartilage repair tissue in middle-aged patients. We tested the hypothesis that in skeletally aged rabbit knees, microdrill holes can be stimulated to remodel the bone plate and induce a more integrated, voluminous and hyaline cartilage repair tissue when treated by subchondral chitosan/blood implants. New Zealand White rabbits (13 or 32 months old, N = 7) received two 1.5 mm diameter, 2 mm depth drill holes in each knee, either left to bleed as surgical controls or press-fit with a 10 kDa (distal hole: 10K) or 40 kDa (proximal hole: 40K) chitosan/blood implant with fluorescent chitosan tracer. Post-operative knee effusion was documented. Repair tissues at day 0 (N = 1) and day 70 post-surgery (N = 6) were analyzed by micro-computed tomography, and by histological scoring and histomorphometry (SafO, Col-2, and Col-1) at day 70. All chitosan implants were completely cleared after 70 days, without increasing transient post-operative knee effusion compared to controls. Proximal control holes had worse osteochondral repair than distal holes. Both implant formulations induced bone remodeling and improved lateral integration of the bone plate at the hole edge. The 40K implant inhibited further bone repair inside 50% of the proximal holes, while the 10K implant specifically induced a "wound bloom" reaction, characterized by decreased bone plate density in a limited zone beyond the initial hole edge, and increased woven bone (WB) plate repair inside the initial hole (P = 0.016), which was accompanied by a more voluminous and hyaline cartilage repair (P hyaline cartilage repair can be promoted by treating acute drill holes with a biodegradable subchondral implant that elicits bone plate resorption followed by anabolic WB repair within a 70-day repair period. Copyright © 2013 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  5. [Effects of in vitro continuous passaging on the phenotype of mouse hyaline chondrocytes and the balance of the extra- cellular matrix].

    Science.gov (United States)

    Linyi, Cai; Xiangli, Kong; Jing, Xie

    2016-06-01

    This study aimed to investigate the effects of in vitro continuous passaging on the morphological phenotype and differentiation characteristics of mouse hyaline chondrocytes, as well as on the balance of the extracellular matrix (ECM). Enzymatic digestion was conducted to isolate mouse hyaline chondrocytes, which expanded over five passages in vitro. Hematoxylin-eosin stain was used to show the changes in chondrocyte morphology. Semi-quantitative polymerase chain reaction was performed to analyze the mRNA changes in the marker genes, routine genes, matrix metalloproteinases (MMPs), and tissue inhibitors of MMPs (TIMPs) in chondrocytes. Zymography was carried out to elucidate changes in gelatinase activities. After continuous expansion in vitro, the morphology of round or polygonal chondrocytes changed to elongated and spindled shape. The expression of marker genes significantly decreased (P 0.05). Meanwhile, the ratio of MMPs/TIMPs was altered. At the protein level, the activities of gelatinases decreased after passaging, especially for P4 and P5 chondrocytes (P cartilage ECM became uncontrollable and led to the imbalance of ECM homeostasis. When hyaline chondrocytes are applied in research on relevant diseases or cartilage tissue engineering, P0-P2 chondrocytes should be used.

  6. Laparoscopic treatment for retroperitoneal hyaline-vascular type localized Castleman's disease (LCD) in the iliac vessel region.

    Science.gov (United States)

    Le, Aiwen; Shan, Lili; Wang, Zhonghai; Dai, Xiaoyun; Xiao, Tianhui; Zhuo, Rong; Yuan, Rui

    2015-01-01

    To improve the understanding, diagnostic levels, and therapeutic levels of retroperitoneal hyaline vascular type LCD in the iliac vessel region. Diagnostic and therapeutic processes of 4 patients with retroperitoneal LCD in the iliac vessel region were retrospectively analyzed. The median ages of the research patients was 31.3 years old, Pelvic vascular dual-source computed tomography (CT) indicated an abnormal pelvic irregular cloddy intensity shadow with heterogeneous densities and punctate calcified lesions. The enhanced scanning showed significantly enhanced lesions and multiple tortuous vascular images inside and around the lesions. Patients' preoperative diagnoses were all "pelvic mass with unknown characteristics", and retroperitoneal masses were successfully stripped off after the laparoscopic surgery. Intra operative findings indicated 1 mass located at the left obturator nerve, 1 at the left internal iliac artery, and 2 at the right external iliac artery. The postoperative pathological reports suggest a diagnosis of Castleman's disease. Retroperitoneal LCD in the iliac vessel region is generally asymptomatic. Preoperative imaging data may help with the diagnosis, but a confirmed diagnosis depends on the results of the pathological examination. Iliac artery embolization is performed prior to laparoscopic mass stripping if the masses have abundant blood supply, while lymphadenectomy is also applied to those with enlarged lymph nodes.

  7. Biostable scaffolds of polyacrylate polymers implanted in the articular cartilage induce hyaline-like cartilage regeneration in rabbits.

    Science.gov (United States)

    Sancho-Tello, María; Forriol, Francisco; Martín de Llano, José J; Antolinos-Turpin, Carmen; Gómez-Tejedor, José A; Gómez Ribelles, José L; Carda, Carmen

    2017-07-05

    To study the influence of scaffold properties on the organization of in vivo cartilage regeneration. Our hypothesis was that stress transmission to the cells seeded inside the pores of the scaffold or surrounding it, which is highly dependent on the scaffold properties, determines the differentiation of both mesenchymal cells and dedifferentiated autologous chondrocytes. 4 series of porous scaffolds made of different polyacrylate polymers, previously seeded with cultured rabbit chondrocytes or without cells, were implanted in cartilage defects in rabbits. Subchondral bone was injured during the surgery to allow blood to reach the implantation site and fill the scaffold pores. At 3 months after implantation, excellent tissue regeneration was obtained, with a well-organized layer of hyaline-like cartilage at the condylar surface in most cases of the hydrophobic or slightly hydrophilic series. The most hydrophilic material induced the poorest regeneration. However, no statistically significant difference was observed between preseeded and non-preseeded scaffolds. All of the materials used were biocompatible, biostable polymers, so, in contrast to some other studies, our results were not perturbed by possible effects attributable to material degradation products or to the loss of scaffold mechanical properties over time due to degradation. Cartilage regeneration depends mainly on the properties of the scaffold, such as stiffness and hydrophilicity, whereas little difference was observed between preseeded and non-preseeded scaffolds.

  8. Hyaline articular cartilage: relaxation times, pulse-sequence parameters and MR appearance at 1.5 T

    Energy Technology Data Exchange (ETDEWEB)

    Chalkias, S.M. [Dept. of Radiology, A.H.E.P.A. General Hospital of the Aristotelian Univ., Thessaloniki (Greece); Pozzi-Mucelli, R.S. [Dept. of Radiology, Univ. of Trieste (Italy); Pozzi-Mucelli, M. [Orthopaedic Clinic, Univ. of Trieste (Italy); Frezza, F. [Dept. of Radiology, Univ. of Trieste (Italy); Longo, R. [Dept. of Radiology, Univ. of Trieste (Italy)

    1994-08-01

    In order to optimize the parameters for the best visualization of the internal architecture of the hyaline articular cartilage a study both ex vivo and in vivo was performed. Accurate T1 and T2 relaxation times of articular cartilage were obtained with a particular mixed sequence and then used for the creation of isocontrast intensity graphs. These graphs subsequently allowed in all pulse sequences (spin echo, SE and gradient echo, GRE) the best combination of repetition time (TR), echo time (TE) and flip angle (FA) for optimization of signal differences between MR cartilage zones. For SE sequences maximum contrast between cartilage zones can be obtained by using a long TR (> 1,500 ms) with a short TE (< 30 ms), whereas for GRE sequences maximum contrast is obtained with the shortest TE (< 15 ms) combined with a relatively long TR (> 400 ms) and an FA greater than 40 . A trilaminar appearance was demonstrated with a superficial and deep hypointense zone in all sequences and an intermediate zone that was moderately hyperintense on SE T1-weighted images, slightly more hyperintense on proton density Rho and SE T2-weighted images and even more hyperintense on GRE images. (orig.)

  9. Injectable glycosaminoglycan-protein nano-complex in semi-interpenetrating networks: A biphasic hydrogel for hyaline cartilage regeneration.

    Science.gov (United States)

    Radhakrishnan, Janani; Subramanian, Anuradha; Sethuraman, Swaminathan

    2017-11-01

    Articular hyaline cartilage regeneration remains challenging due to its less intrinsic reparability. The study develops injectable biphasic semi-interpenetrating polymer networks (SIPN) hydrogel impregnated with chondroitin sulfate (ChS) nanoparticles for functional cartilage restoration. ChS loaded zein nanoparticles (∼150nm) prepared by polyelectrolyte-protein complexation were interspersed into injectable SIPNs developed by blending alginate with poly(vinyl alcohol) and calcium crosslinking. The hydrogel exhibited interconnected porous microstructure (39.9±5.8μm pore diameter, 57.7±5.9% porosity), 92% swellability and >350Pa elastic modulus. Primary chondrocytes compatibility, chondrocyte-matrix interaction with cell-cell clustering and spheroidal morphology was demonstrated in ChS loaded hydrogel and long-term (42days) proliferation was also determined. Higher fold expression of cartilage-specific genes sox9, aggrecan and collagen-II was observed in ChS loaded hydrogel while exhibiting poor expression of collagen-I. Immunoblotting of aggregan and collagen II demonstrate favorable positive influence of ChS on chondrocytes. Thus, the injectable biphasic SIPNs could be promising composition-mimetic substitute for cartilage restoration at irregular defects. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Membrane dynamics

    DEFF Research Database (Denmark)

    Bendix, Pól Martin

    2015-01-01

    Current topics include membrane-protein interactions with regard to membrane deformation or curvature sensing by BAR domains. Also, we study the dynamics of membrane tubes of both cells and simple model membrane tubes. Finally, we study membrane phase behavior which has important implications...... for the lateral organization of membranes as wells as for physical properties like bending, permeability and elasticity...

  11. The role of complement receptors type 1 (CR1, CD35) and 2 (CR2, CD21) in promoting C3 fragment deposition and membrane attack complex formation on normal peripheral human B cells

    DEFF Research Database (Denmark)

    Nielsen, Claus Henrik; Pedersen, Morten Løbner; Marquart, Hanne Vibeke

    2002-01-01

    Normal human B lymphocytes are known to activate the alternative pathway (AP) of complement, leading to C3-fragment deposition and membrane attack complex (MAC) formation. The process is mediated via complement receptor type 2 (CR2, CD21), with complement receptor type 1 (CR1, CD35) playing...... a subsidiary role. In this study, we examine the relative contributions of CR1 and CR2 to the deposition of C3 fragments and MAC on B lymphocytes under circumstances where all complement pathways are operational. C3-fragment deposition and MAC formation were assessed on human peripheral B lymphocytes......) bearing CR1, however, markedly reduced both C3-fragment deposition and MAC formation. Our data suggest that C3-fragment deposition and MAC formation on B lymphocytes in vivo may involve both AP and classical pathway activation, with CR1 contributing significantly to the latter. On the other hand...

  12. Curcumin disorders 1,2-dipalmitoyl-sn-glycero-3-phosphocholine membranes and favors the formation of nonlamellar structures by 1,2-dielaidoyl-sn-glycero-3-phosphoethanolamine.

    Science.gov (United States)

    Pérez-Lara, Angel; Ausili, Alessio; Aranda, Francisco J; de Godos, Ana; Torrecillas, Alejandro; Corbalán-García, Senena; Gómez-Fernández, Juan C

    2010-08-05

    Curcumin is a polyphenol present in turmeric, a spice widely used in Asian traditional medicine and cooking. It has many and diverse biological effects and is incorporated in cell membranes. This paper describes the mode in which curcumin modulates the physical properties of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dielaidyl-sn-glycero-3-phosphoetnanolamine (DEPE) multilamellar membranes. Curcumin disordered DPPC membranes at temperatures below T(c) as seen by DSC, FT-IR, (2)H NMR, WAXD, and SAXD. The decrease induced by curcumin in T(c) suggested that it is oriented in the bilayer with its main axis parallel to the acyl chains. Above T(c), too, curcumin introduced disorder as seen by infrared spectroscopy which showed that curcumin also alters the conformation of the polar group of DPPC, increasing the percentage of unhydrated C=O groups, but does not form hydrogen bonds with either the C=O group or the phosphate group of DPPC. Small angle X-ray diffraction showed a notable increase in the repeating spacings as a result of the presence of curcumin, suggesting the formation of a rippled phase. Increasing concentrations of curcumin progressively modified the onset and completion of the phase transition and also DeltaH up to a 6:1 DPPC/curcumin molar ratio. A further increase of curcumin concentration did not produce effects on the transition parameters, suggesting that there is a limit for the solubility of curcumin in DPPC. Additionally, when DEPE was used to test the effect of curcumin on the phospholipid polymorphism, it was found that the temperature at which the H(II) phase is formed decreased, indicating that curcumin favors negative curvature of the membrane, which may be important for explaining its effect on membrane dynamics and on membrane proteins or on proteins which may be activated through membrane insertion.

  13. Towards bio-silicon interfaces: formation of an ultra-thin self-hydrated artificial membrane composed of dipalmitoylphosphatidylcholine (DPPC) and chitosan deposited in high vacuum from the gas-phase.

    Science.gov (United States)

    Retamal, María J; Cisternas, Marcelo A; Gutierrez-Maldonado, Sebastian E; Perez-Acle, Tomas; Seifert, Birger; Busch, Mark; Huber, Patrick; Volkmann, Ulrich G

    2014-09-14

    The recent combination of nanoscale developments with biological molecules for biotechnological research has opened a wide field related to the area of biosensors. In the last years, device manufacturing for medical applications adapted the so-called bottom-up approach, from nanostructures to larger devices. Preparation and characterization of artificial biological membranes is a necessary step for the formation of nano-devices or sensors. In this paper, we describe the formation and characterization of a phospholipid bilayer (dipalmitoylphosphatidylcholine, DPPC) on a mattress of a polysaccharide (Chitosan) that keeps the membrane hydrated. The deposition of Chitosan (~25 Å) and DPPC (~60 Å) was performed from the gas phase in high vacuum onto a substrate of Si(100) covered with its native oxide layer. The layer thickness was controlled in situ using Very High Resolution Ellipsometry (VHRE). Raman spectroscopy studies show that neither Chitosan nor DPPC molecules decompose during evaporation. With VHRE and Atomic Force Microscopy we have been able to detect phase transitions in the membrane. The presence of the Chitosan interlayer as a water reservoir is essential for both DPPC bilayer formation and stability, favoring the appearance of phase transitions. Our experiments show that the proposed sample preparation from the gas phase is reproducible and provides a natural environment for the DPPC bilayer. In future work, different Chitosan thicknesses should be studied to achieve a complete and homogeneous interlayer.

  14. Towards bio-silicon interfaces: Formation of an ultra-thin self-hydrated artificial membrane composed of dipalmitoylphosphatidylcholine (DPPC) and chitosan deposited in high vacuum from the gas-phase

    Energy Technology Data Exchange (ETDEWEB)

    Retamal, María J., E-mail: moretama@uc.cl; Cisternas, Marcelo A.; Seifert, Birger; Volkmann, Ulrich G. [Instituto de Física, Pontificia Universidad Católica de Chile, Avda. Vicuña Mackenna 4860, 7820436 Santiago (Chile); Centro de Investigación en Nanotecnología y Materiales Avanzados (CIEN-UC), Pontificia Universidad Católica de Chile, Avda. Vicuña Mackenna 4860, 7820436 Santiago (Chile); Gutierrez-Maldonado, Sebastian E.; Perez-Acle, Tomas [Computational Biology Lab (DLab), Fundación Ciencia y Vida, Av. Zañartu 1482, Santiago (Chile); Centro Interdisciplinario de Neurociencias de Valparaiso (CINV), Universidad de Valparaiso, Pasaje Harrington 287, Valparaiso (Chile); Busch, Mark; Huber, Patrick [Institute of Materials Physics and Technology, Hamburg University of Technology (TUHH), D-21073 Hamburg-Harburg (Germany)

    2014-09-14

    The recent combination of nanoscale developments with biological molecules for biotechnological research has opened a wide field related to the area of biosensors. In the last years, device manufacturing for medical applications adapted the so-called bottom-up approach, from nanostructures to larger devices. Preparation and characterization of artificial biological membranes is a necessary step for the formation of nano-devices or sensors. In this paper, we describe the formation and characterization of a phospholipid bilayer (dipalmitoylphosphatidylcholine, DPPC) on a mattress of a polysaccharide (Chitosan) that keeps the membrane hydrated. The deposition of Chitosan (∼25 Å) and DPPC (∼60 Å) was performed from the gas phase in high vacuum onto a substrate of Si(100) covered with its native oxide layer. The layer thickness was controlled in situ using Very High Resolution Ellipsometry (VHRE). Raman spectroscopy studies show that neither Chitosan nor DPPC molecules decompose during evaporation. With VHRE and Atomic Force Microscopy we have been able to detect phase transitions in the membrane. The presence of the Chitosan interlayer as a water reservoir is essential for both DPPC bilayer formation and stability, favoring the appearance of phase transitions. Our experiments show that the proposed sample preparation from the gas phase is reproducible and provides a natural environment for the DPPC bilayer. In future work, different Chitosan thicknesses should be studied to achieve a complete and homogeneous interlayer.

  15. Towards bio-silicon interfaces: Formation of an ultra-thin self-hydrated artificial membrane composed of dipalmitoylphosphatidylcholine (DPPC) and chitosan deposited in high vacuum from the gas-phase

    Science.gov (United States)

    Retamal, María J.; Cisternas, Marcelo A.; Gutierrez-Maldonado, Sebastian E.; Perez-Acle, Tomas; Seifert, Birger; Busch, Mark; Huber, Patrick; Volkmann, Ulrich G.

    2014-09-01

    The recent combination of nanoscale developments with biological molecules for biotechnological research has opened a wide field related to the area of biosensors. In the last years, device manufacturing for medical applications adapted the so-called bottom-up approach, from nanostructures to larger devices. Preparation and characterization of artificial biological membranes is a necessary step for the formation of nano-devices or sensors. In this paper, we describe the formation and characterization of a phospholipid bilayer (dipalmitoylphosphatidylcholine, DPPC) on a mattress of a polysaccharide (Chitosan) that keeps the membrane hydrated. The deposition of Chitosan (˜25 Å) and DPPC (˜60 Å) was performed from the gas phase in high vacuum onto a substrate of Si(100) covered with its native oxide layer. The layer thickness was controlled in situ using Very High Resolution Ellipsometry (VHRE). Raman spectroscopy studies show that neither Chitosan nor DPPC molecules decompose during evaporation. With VHRE and Atomic Force Microscopy we have be