Proceedings of the 17th Southern Biomedical Engineering Conference最新文献_第10页

Soft Tissue Engineering In Vivo with PGLA Scaffolds and PLGA/PEG Microsphere Long Term Delivery of Lipogenic Factors 用聚乳酸支架和聚乳酸/聚乙二醇微球长期递送致脂因子的活体软组织工程

Proceedings of the 17th Southern Biomedical Engineering Conference Pub Date : 1998-02-06 DOI: 10.1109/SBEC.1998.666751

E. Yuksel, R. Ray, S. Wamsley, A. Weinfeld, J. Waugh, M. Widmer, R. Cleek, A. Mikos, S. Shenaq, M. Spira

{"title":"Soft Tissue Engineering In Vivo with PGLA Scaffolds and PLGA/PEG Microsphere Long Term Delivery of Lipogenic Factors","authors":"E. Yuksel, R. Ray, S. Wamsley, A. Weinfeld, J. Waugh, M. Widmer, R. Cleek, A. Mikos, S. Shenaq, M. Spira","doi":"10.1109/SBEC.1998.666751","DOIUrl":"https://doi.org/10.1109/SBEC.1998.666751","url":null,"abstract":"Introduction Soft tissue is frequently used to reconstitute defects in reconstructive surgery. With the advances in bioengineering, the ability to tissues in vivo for reconstructive purposes will someday be reality. We have developed an animal model for the investigation of in vivo tissue generation. Our model includes the use of a biodegradable PLGA scaffold supporr structure used in conjunction with the long-term delivery of t the four timeexogenous lipogenic and angiogenic peptide growth factors via PLGAPEG microspheres. The objectives of this present investigation were twofold. First, we sought to determine the in vivo persistence of our over time. Second, we ntial for soft tissue generation with the use of the scaffold and microsphere longterm delivery of insulin, IGF, and bFGF. Materials and Methods Part 1: Composite foams of PLGA (5050) were produced by a particulate leaching technique using 300-500 micrometer NaCl particles as a porogen. A cylinder with a diameter of 12 mm was vulcanized from the PLGA and disks with a height of 5 mm were sequentially cut from that form. The disks were implanted in the dorsum of male Sprague Dawley rats. The entire implant region was harvested en bloc from four time-point animal groups at 3, 7, 14, and 21 days. The height and width of the explanted disks were measured on hematoxylin and eosin stained sections through the midpoint. The in V I V O Axial Persistence Product (APP) was calculated by multiplying the two values. Part 2: PLGNPEG microspheres containing insulin, IGF, and bFGF were manufactured using a double-emulsion-solvent-extraction technique. The microspheres were introduced into the pores of PLGA (75125 and 50/50) hemispheres and the hemispheres were implanted in the latissimus dorsi observation at mult","PeriodicalId":122159,"journal":{"name":"Proceedings of the 17th Southern Biomedical Engineering Conference","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124726826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Method For Driving A Dynamic Musculoskeletal Model Using Processed Electromyographic Data 一种利用处理过的肌电图数据驱动动态肌肉骨骼模型的方法

Proceedings of the 17th Southern Biomedical Engineering Conference Pub Date : 1998-02-06 DOI: 10.1109/SBEC.1998.666679

R. Gonzalez, R. E. Barr, L. Abraham

{"title":"A Method For Driving A Dynamic Musculoskeletal Model Using Processed Electromyographic Data","authors":"R. Gonzalez, R. E. Barr, L. Abraham","doi":"10.1109/SBEC.1998.666679","DOIUrl":"https://doi.org/10.1109/SBEC.1998.666679","url":null,"abstract":"Pro tocol Yame €le PIS Flexion at Pronation (F@P) 0.407 0.549 Introduction A methodology has been developed and implemented for processing EMG activity as an input to a dynamic musculoskeletal model [1,2] of the human elbow joint complex (EJC). The major focus of the processing scheme was to transform EMG frequency and amplitude information into a representation for muscle activation, which in turn served as an input to drive the model in predicting forces in eight major muscles about the elbow. Methodology Ballistic movements were executed for ten experimental protocols in various combinations of elbow flexion (0. extension (e), forearm pronation (p), and forearm supination (s). EMG signals were gathered from eight major muscles about the eIbow: biceps brachi, brachialis, brachioradialis. mceps brachii, supinator, pronator teres, anconeus. and pronator quadratus. Raw EMG signals were processed as shown in Figure 1. The signals were First digitally filtered (band-pass. 50-200 Hz), then Fully rectified. and again digitally filtered (low-pass. 10 Hz). The data were then dynamically normalized to 70% of the maximum EMG value, and finally a muscle-specific multiplication factor was applied. The biomechanical WC model represents a quantitative system in which the general components are muscular and skeletal. Input to the model consisted of EMG-driven muscle activation. and output was represented by angular position, velocity, and acceleration for two DOFs (Ye and p/s). The driven kinematic data (yp) predicted by the EX model were then correlated with the experimental kinematic data (ym) using a normalized absolute deviation calculation (E) across all k sample points:","PeriodicalId":122159,"journal":{"name":"Proceedings of the 17th Southern Biomedical Engineering Conference","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121656732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Long-Term Stability Of Biodegradable Polymers 生物可降解聚合物的长期稳定性

Proceedings of the 17th Southern Biomedical Engineering Conference Pub Date : 1998-02-06 DOI: 10.1109/SBEC.1998.666675

C. T. Williams, J. Middleton, K. R. Sims, R.P. Swaim, D. Whitfield, J. C. Yarbrough

引用次数: 4

Analysis Of Tissues Collected During Primary And Revision Hip Arthroplasty 初次和翻修髋关节置换术中收集的组织分析

Proceedings of the 17th Southern Biomedical Engineering Conference Pub Date : 1998-02-06 DOI: 10.1109/SBEC.1998.666664

M. Tucci, A. Tsao, J. Hughes

{"title":"Analysis Of Tissues Collected During Primary And Revision Hip Arthroplasty","authors":"M. Tucci, A. Tsao, J. Hughes","doi":"10.1109/SBEC.1998.666664","DOIUrl":"https://doi.org/10.1109/SBEC.1998.666664","url":null,"abstract":"that when foreign introduced into a host a sequence of biologicdl owing the marerial to become thin the tissues. The reactive form between the implant and bone an lead to late aseptic loosening. This type of loosening is implicated to be the most a m o n reason for implant failure. It is beIieved that more mature aseptic loosening involves abnormaI and even normal mechanical suesses can Iead to the production of m pic wear particles. Submicron wear p can either be trapped within the joint or to adjacent tissues where they can init de of inflammatory reactions that allow for the recruitment of M a , lymphs and with time a fibrous ,“doma like tissue will develop around the implant. The cell types found at the interface are capable of secreting bone-resorbing cytokines. Ln addition to the osteouophic factors (cytokines), biologicd oxidation of tissues has also been reco,onized as a primary event in the pad.lo,oenesis of many diseases. Reactive ies of O._ and hydroxyl radicals (OH? ar rmed within norma1 biologica1 tissues and propagate along the ’ phospholipid membranes which can cause dative damage of tissues. n e goal ‘of this ine the levels of cytokines and e herface tiSsues reuieved ,","PeriodicalId":122159,"journal":{"name":"Proceedings of the 17th Southern Biomedical Engineering Conference","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132688346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Blood Viscoelasticity Changes In Cardiac Surgery 心脏手术中的血液粘弹性变化

Proceedings of the 17th Southern Biomedical Engineering Conference Pub Date : 1998-02-06 DOI: 10.1109/SBEC.1998.666710

G. Thurston, N. Henderson, A. Undar, J. Calhoon

引用次数: 1

Development And Application Of Unique Skin-Coating Materials 独特皮肤涂层材料的开发与应用

Proceedings of the 17th Southern Biomedical Engineering Conference Pub Date : 1998-02-06 DOI: 10.1109/SBEC.1998.666689

M. Fan, D.P. Kreig, G. Siegel, H. R. Rawls

引用次数: 1

Inhibitory Effects Of /spl beta/3 Integrin Antibody On The Migration Of Vascular Adventitial Fibroblasts Induced By Basic Fibroblast Growth Factor /spl β /3整合素抗体对碱性成纤维细胞生长因子诱导的血管内皮成纤维细胞迁移的抑制作用

Proceedings of the 17th Southern Biomedical Engineering Conference Pub Date : 1998-02-06 DOI: 10.1109/SBEC.1998.666608

Guizhen Liu, S. Eskin, A. Mikos

引用次数: 0

Perfusion And Temperature Measurements In Hyperthermic Canine Prostates 热疗犬前列腺灌注和温度测量

Proceedings of the 17th Southern Biomedical Engineering Conference Pub Date : 1998-02-06 DOI: 10.1109/SBEC.1998.666692

D. Y. Yuan, L.X. Xu, Liang Zhu, K. Holmes, J. W. Valvano

{"title":"Perfusion And Temperature Measurements In Hyperthermic Canine Prostates","authors":"D. Y. Yuan, L.X. Xu, Liang Zhu, K. Holmes, J. W. Valvano","doi":"10.1109/SBEC.1998.666692","DOIUrl":"https://doi.org/10.1109/SBEC.1998.666692","url":null,"abstract":"T -A variety of heat transfer modeling studies have been performed in conjunction with the development of thermally-based treatments for benign prostatic hyperplasia. Most studies have assumed prostate perfusion values and responses extrapolated fiom other organs and animals due to the lack of prostate perfusion data. Simultaneous measurements of temperature and perfusion will enable a more rudimentary approach to developing bioheat transfer models. In this study, perfusion and temperatures were measured at various locations within each of the four canine prostates subjected to a uamurethral microwave thermal source. The total number of the perfusion sampling points coupled with temperature is 15. Colored microspheres were used to measure perfusion due to its simplicity compared with radioactively-labeled microspheres and because the . microsphere trapping method is regarded as a standard. 'Temperatures were measured using miniature thermistors. The prostate temperatures were raised to 40 45 OC by 5W step increments of the microwave power at hourly intervals to 15W. Temperatures and perfusion were measured at baseline, and at the beginning andend of each heating interval. Thus, the periods between perfusion samples were approximately either 5 or 60 minutes. Under baseline conditions, the temperature fluctuations within the prostate were approximately 0.3 'C. A relaave dispersion estimate of 15% was derived fiom one dog for the fluctuations in baseline perfusion. Thus, changes in absolute perfusion and temperature greater than 15% and 0.3 OC, respectively, were considered to be substantial changes. As heating progressed, a variety of substantial changes were observed, but no uniform pattern emerged. However, the measurements included changes typically expected for hyperthermia: 1.) an initial perfusion increase associated with elevating the baseline temperature, 2.) a Perfusion return towards baseline after this initial increase, and 3.) a dramatic increase in perfusion at elevated temperatures. The initial perfusion increases 1 h 2 1.03 ; I 0 2 0.80 6","PeriodicalId":122159,"journal":{"name":"Proceedings of the 17th Southern Biomedical Engineering Conference","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122728002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Platelet Adhesion And Activation On The Material Surfaces Of Gyro Centrifugal Pump 陀螺仪离心泵材料表面血小板的粘附与活化

Proceedings of the 17th Southern Biomedical Engineering Conference Pub Date : 1998-02-06 DOI: 10.1109/SBEC.1998.666759

S. Yamane, G. Ohtsuka, K. Nakata, M. Yoshikawa, J. Glueck, A. Sueoka, Y. Takami, Y. Nosé

引用次数: 0

Regulation Of Axon Extension By Chondroitin Sulfate Glycosaminoglycans 硫酸软骨素糖胺聚糖对轴突延伸的调控

Proceedings of the 17th Southern Biomedical Engineering Conference Pub Date : 1998-02-06 DOI: 10.1109/SBEC.1998.666607

M. Navarro, B. S. Thomas, R. LeBaron

{"title":"Regulation Of Axon Extension By Chondroitin Sulfate Glycosaminoglycans","authors":"M. Navarro, B. S. Thomas, R. LeBaron","doi":"10.1109/SBEC.1998.666607","DOIUrl":"https://doi.org/10.1109/SBEC.1998.666607","url":null,"abstract":"Introduction Axon extension and guidance is a fundamental process of tissue remodeling. Likewise, innervation of engineered material may be an important component for the successful integration of material into human tissue. We are studying components of the extracellular matrix (ECM) that regulate axon movement. This study focuses on the biological activity of chondroitin sulfate glycosaminoglycans (CS-GAGS). These are linear, unbranched, sulfated carbohydrate chains composed of alternating galactosamine and hexuronic acid. CS-GAGS are found in most tissues and influence axon extension of several neuronal cell types. Interestingly, cytokines such as Transforming Growth Factor-P (TGF-j3) may alter the quantity of CS-GAGS in a given tissue. This is believed to occur by increasing the GAG chain length and chain number. Thus, the quantity of GAG in a tissue can be modified by cytokines that are present during tissue remodeling. The observation that CS-GAG content in the ECM may be upregulated by certain cytokines and that CS-GAGS influence neurite extension formed the following hypothesis: The concentration of CS-GAG within a tissue may regulate the degree of axon extension. We have examined the effects oft CS-GAGS on axon behavior. This was accomplished by culturing neurons on a substrate containing a region with a high content of CS-GAG. Materials and Methods Cells established from a transplantable rat adrenal pheochromocytoma, (PC12 cells) were maintained in OPTI-MEM Medium with 5% heat-treated fetal bovine serum and seeded onto rat tail type I collagen (50 yglml) coated dishes. One day after seeding, cells were treated with 100 nglml of nerve growth factor (NGF). PC12 cells were maintained in OPTI-MEM supplemented with 50 nglml NGF. These cells were used as a source for neurite extension experiments. Culture dishes were coated with nitrocellulose in methanol and subsequently coated with a solution of type I collagen (50 pg/ml). CS-GAGS (10 mg/ml) were applied at specific regions on the collagen substrate and' then seeded with PC12 cells. For control experiments, culture dishes were coated as described above, with sterile water applied at specific regions on the collagen substratum. Results Fig. 1 shows phase-contrast photomicrographs of NGF-treated PC12 cells cultured in the absence and presence of CSGAGs. In Fig. lA, extensive neurite extension in cultures of NGF-treated PC12 cells is seen in regions containing collagen and a cross pattern soaked with sterile water. The PC12 cells readily extended neurites on the collagen substratum. However, as seen in Fig. lB, neurite extension in regions containing CSGAGs was greatly reduced. Discussion In vitro, CS-GAGS on collagen function as a bamer to axon elongation. This suggests that CS-GAG may prevent axon growth cone contact with an appropriate ECM ligand and may effectively inhibit elongation. It is therefore postulated that the concentration of GAG within a tissue may modulate axon extension and m","PeriodicalId":122159,"journal":{"name":"Proceedings of the 17th Southern Biomedical Engineering Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131062414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0