Pub Date : 1995-04-07DOI: 10.1109/SBEC.1995.514459
S. Saha
Health care management costs rise yearly, especially in the areas of personnel and the expenses of generating and maintaining the patients' records. A substantial informational burden is incurred with each patient visit to a health professional, and patients' needs are often lost in the shuffle of medical records, insurance information, and red tape. However during the last few years significant progress has been made in the development of clinically useful medical decision support system to assist the health care provider. Earlier efforts to implement computer-based patient records mainly used keyboard entry, but with the latest technology, voice activated clinical reporting systems could be a central component of such a computer-based system in the future. Several groups are in the process of developing portable data management device. This will allow the clinicians to have on-line readily transferable patient records, decision making support and searching of remote databases to better analyze complex health care delivery problems. When the medical transcriptions are forwarded to an off-site location, this unique device will reduce the time and the cost of re-recording and transmission. This device will help the user to maintain and update the data remotely and instantly. It will also provide immediate information updates and database manipulations for all aspects of medical data management, provide portable multiple and simultaneous access to complete database information. These will significantly reduce paperwork and personnel costs.
{"title":"The new age electronic patient record system","authors":"S. Saha","doi":"10.1109/SBEC.1995.514459","DOIUrl":"https://doi.org/10.1109/SBEC.1995.514459","url":null,"abstract":"Health care management costs rise yearly, especially in the areas of personnel and the expenses of generating and maintaining the patients' records. A substantial informational burden is incurred with each patient visit to a health professional, and patients' needs are often lost in the shuffle of medical records, insurance information, and red tape. However during the last few years significant progress has been made in the development of clinically useful medical decision support system to assist the health care provider. Earlier efforts to implement computer-based patient records mainly used keyboard entry, but with the latest technology, voice activated clinical reporting systems could be a central component of such a computer-based system in the future. Several groups are in the process of developing portable data management device. This will allow the clinicians to have on-line readily transferable patient records, decision making support and searching of remote databases to better analyze complex health care delivery problems. When the medical transcriptions are forwarded to an off-site location, this unique device will reduce the time and the cost of re-recording and transmission. This device will help the user to maintain and update the data remotely and instantly. It will also provide immediate information updates and database manipulations for all aspects of medical data management, provide portable multiple and simultaneous access to complete database information. These will significantly reduce paperwork and personnel costs.","PeriodicalId":332563,"journal":{"name":"Proceedings of the 1995 Fourteenth Southern Biomedical Engineering Conference","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131240396","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}
Pub Date : 1995-04-07DOI: 10.1109/SBEC.1995.514471
D. Schieb
Falling is a leading cause of morbidity and mortality in the U.S. Several factors can contribute to injuries resulting from tripping, slipping and falling during locomotion such as surface condition, transitions and the degree of walkway evenness. Because walkway unevenness has been largely unexamined, the purpose of this study was to evaluate the extent to which gait kinetics change with uneven walkway surface heights. In this study, subjects walked at a constant velocity over a walkway, whose surface for various trials was positioned above, below, and level with respect to multicomponent force measuring plate. Ground reaction forces (GRF) were recorded from a single step when the subject stepped up or down onto the force plate during gait. Averaged trials from three step-up and two step-down heights were compared to level gait trials. GRF parameters included peak force components, center of pressure and temporal measures. Significant differences in GRF measures were found between the level condition and step-up heights >2.5 cm and step-down heights >-1.5 cm. No differences were found between the level condition and a step-up height of 0.7 cm. The results suggest that a walkway unevenness of >2.5 cm step-up and >1.5 cm step-down may contribute to initiating a trip, stumble or fall since the GRF are significantly altered with these conditions. However, negotiating a step-up of <2.5 cm or step-down of <0.7 cm produces gait kinetic measures similar to walking on a level surface, and therefore may not predispose one to a trip or stumble.
{"title":"Walkway surface heights and ground reaction forces","authors":"D. Schieb","doi":"10.1109/SBEC.1995.514471","DOIUrl":"https://doi.org/10.1109/SBEC.1995.514471","url":null,"abstract":"Falling is a leading cause of morbidity and mortality in the U.S. Several factors can contribute to injuries resulting from tripping, slipping and falling during locomotion such as surface condition, transitions and the degree of walkway evenness. Because walkway unevenness has been largely unexamined, the purpose of this study was to evaluate the extent to which gait kinetics change with uneven walkway surface heights. In this study, subjects walked at a constant velocity over a walkway, whose surface for various trials was positioned above, below, and level with respect to multicomponent force measuring plate. Ground reaction forces (GRF) were recorded from a single step when the subject stepped up or down onto the force plate during gait. Averaged trials from three step-up and two step-down heights were compared to level gait trials. GRF parameters included peak force components, center of pressure and temporal measures. Significant differences in GRF measures were found between the level condition and step-up heights >2.5 cm and step-down heights >-1.5 cm. No differences were found between the level condition and a step-up height of 0.7 cm. The results suggest that a walkway unevenness of >2.5 cm step-up and >1.5 cm step-down may contribute to initiating a trip, stumble or fall since the GRF are significantly altered with these conditions. However, negotiating a step-up of <2.5 cm or step-down of <0.7 cm produces gait kinetic measures similar to walking on a level surface, and therefore may not predispose one to a trip or stumble.","PeriodicalId":332563,"journal":{"name":"Proceedings of the 1995 Fourteenth Southern Biomedical Engineering Conference","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130099355","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}
Pub Date : 1995-04-07DOI: 10.1109/SBEC.1995.514462
M. Refojo
From the economic and social significance the most important applications of polymers in ophthalmology are in contact and intraocular lenses, as well as in viscoelastic polymer solutions used for tissue protection during intraocular surgery. Although needed by fewer patients, scleral implants, silicone oils and perfluorocarbon liquids are important in the surgery to repair retinal detachments. Polymeric devices are also used for the treatment of complicated glaucoma, as artificial corneas and for sustained drug delivery on and into the eye. Some of the implants and devices use in ophthalmology are made with commercial polymers. However, new polymers with specific properties are used to manufacture contact lenses and surgical implants to correct or to restore vision.
{"title":"Polymers and devices in ophthalmology","authors":"M. Refojo","doi":"10.1109/SBEC.1995.514462","DOIUrl":"https://doi.org/10.1109/SBEC.1995.514462","url":null,"abstract":"From the economic and social significance the most important applications of polymers in ophthalmology are in contact and intraocular lenses, as well as in viscoelastic polymer solutions used for tissue protection during intraocular surgery. Although needed by fewer patients, scleral implants, silicone oils and perfluorocarbon liquids are important in the surgery to repair retinal detachments. Polymeric devices are also used for the treatment of complicated glaucoma, as artificial corneas and for sustained drug delivery on and into the eye. Some of the implants and devices use in ophthalmology are made with commercial polymers. However, new polymers with specific properties are used to manufacture contact lenses and surgical implants to correct or to restore vision.","PeriodicalId":332563,"journal":{"name":"Proceedings of the 1995 Fourteenth Southern Biomedical Engineering Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130269447","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}
Pub Date : 1995-04-07DOI: 10.1109/SBEC.1995.514424
C. He, M. R. Roach
Dissecting aneurysms, or dissections, occur in large arteries by creating a false lumen in the media which is parallel to the true lumen. A tensile force is needed to tear the arterial wall in dissections. This tensile force could be produced in response to the pressure in the false lumen. In this study, tearing pressure was investigated. The studies were done in vitro on fresh isolated porcine thoracic aortas which were pressurized to 130 mmHg (physiological mean pressure). A volume of diluted India ink was injected into the media of the aortic wall to create a cavity called a "bleb". As the size of the bleb increased, the media was dissected. The difference between the pressure inside the bleb and that in the lumen was measured, and defined as tearing pressure. Ten pig thoracic aortas were studied. The results showed that tearing pressure decreased with the volume of blebs at the beginning when the blebs were first formed, and then reached a constant pressure after the shape of blebs did not change. The minimum tearing pressure required for the propagation of dissections is called propagation pressure which is 52/spl plusmn/10(SD) mmHg (n=10) in the range of physiological pressure, indicating that the propagation of dissection might be possible in vivo under physiological conditions. Based on the assumptions that each aortic wall has a constant Young's modulus at large strains and a maximum strain, and shear stress is not an important fact involved in dissections, a mathematical model is established for dissections of the aortic wall. The tearing pressure was inversely proportional to both the radii of blebs and the tangents of the angles at the leading edge of dissections before the blebs had a fixed shape, and then kept as a constant when the shape of blebs did not change. The model explained the change of tearing pressure with the geometry of blebs, and predicted tearing pressure would be lower in old human aortas than in young ones.
{"title":"Changes in tearing pressure with the geometry of dissections in porcine aortas","authors":"C. He, M. R. Roach","doi":"10.1109/SBEC.1995.514424","DOIUrl":"https://doi.org/10.1109/SBEC.1995.514424","url":null,"abstract":"Dissecting aneurysms, or dissections, occur in large arteries by creating a false lumen in the media which is parallel to the true lumen. A tensile force is needed to tear the arterial wall in dissections. This tensile force could be produced in response to the pressure in the false lumen. In this study, tearing pressure was investigated. The studies were done in vitro on fresh isolated porcine thoracic aortas which were pressurized to 130 mmHg (physiological mean pressure). A volume of diluted India ink was injected into the media of the aortic wall to create a cavity called a \"bleb\". As the size of the bleb increased, the media was dissected. The difference between the pressure inside the bleb and that in the lumen was measured, and defined as tearing pressure. Ten pig thoracic aortas were studied. The results showed that tearing pressure decreased with the volume of blebs at the beginning when the blebs were first formed, and then reached a constant pressure after the shape of blebs did not change. The minimum tearing pressure required for the propagation of dissections is called propagation pressure which is 52/spl plusmn/10(SD) mmHg (n=10) in the range of physiological pressure, indicating that the propagation of dissection might be possible in vivo under physiological conditions. Based on the assumptions that each aortic wall has a constant Young's modulus at large strains and a maximum strain, and shear stress is not an important fact involved in dissections, a mathematical model is established for dissections of the aortic wall. The tearing pressure was inversely proportional to both the radii of blebs and the tangents of the angles at the leading edge of dissections before the blebs had a fixed shape, and then kept as a constant when the shape of blebs did not change. The model explained the change of tearing pressure with the geometry of blebs, and predicted tearing pressure would be lower in old human aortas than in young ones.","PeriodicalId":332563,"journal":{"name":"Proceedings of the 1995 Fourteenth Southern Biomedical Engineering Conference","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126040500","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}
Pub Date : 1995-04-07DOI: 10.1109/SBEC.1995.514498
A. Shirazi-Adl, H. Ranu
A 3-D finite element model has been developed and is being used to analyse the effect of alteration in the nucleus fluid content on the overall mechanics of a lumbar motion segment. The results show that a change in the nucleus volume directly affected the intradiscal pressure. Similar results are also obtained in an experimental study where intradiscal pressures are measured by infusing a small volume of saline solution in an intervertebral disc in a slow and continuous fashion by a pump.
{"title":"3-D finite element modeling of human spinal discs and correlation with volume-pressure relation due to loading","authors":"A. Shirazi-Adl, H. Ranu","doi":"10.1109/SBEC.1995.514498","DOIUrl":"https://doi.org/10.1109/SBEC.1995.514498","url":null,"abstract":"A 3-D finite element model has been developed and is being used to analyse the effect of alteration in the nucleus fluid content on the overall mechanics of a lumbar motion segment. The results show that a change in the nucleus volume directly affected the intradiscal pressure. Similar results are also obtained in an experimental study where intradiscal pressures are measured by infusing a small volume of saline solution in an intervertebral disc in a slow and continuous fashion by a pump.","PeriodicalId":332563,"journal":{"name":"Proceedings of the 1995 Fourteenth Southern Biomedical Engineering Conference","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134368085","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}
Pub Date : 1995-04-07DOI: 10.1109/SBEC.1995.514435
L.S. Popich, A. M. Rust-Dawicki, J. Klawitter, J. F. Kay, S. Cook
Low-temperature isotropic (LTI) pyrolytic carbon implants (Carbon Implants, Austin, TX) with smooth and grooved surfaces were evaluated using the canine transcortical plug model. The implants were evaluated with and without a 50-75 /spl mu/m hydroxylapatite (HA) coating (Bio-Interfaces, Inc., San Diego, CA). Four adult mongrel dogs were used each receiving five transcortical implants bilaterally in the femur. The implants were evaluated mechanically and histologically at periods of 3, 4, and 6 weeks postoperatively. Mechanical pushout testing was performed to determine interface attachment strength and stiffness. Histologic sections were evaluated for interface tissue characterization, percent bone apposition, and mode of interface pushout failure. Statistical analysis revealed that RA coating significantly increased interface shear strength and stiffness of smooth pyrolytic carbon implants. A grooved surface texture resulted in improved mechanical attachment strength compared to smooth surface texture and was unaffected by the application of HA coating. Histologic evaluation showed a significant amount of direct implant-bone apposition with little or no fibrous tissue present. HA-coated implants had a significantly greater amount of direct bone apposition with both smooth and textured surfaces compared to uncoated implants.
低温各向同性(LTI)热解碳植入物(carbon implant, Austin, TX)具有光滑和沟槽的表面，使用犬经皮质塞模型进行评估。植入物在使用和不使用50-75 /spl mu/m羟基磷灰石(HA)涂层时进行评估(Bio-Interfaces, Inc.， San Diego, CA)。使用4只成年杂种狗，每只接受5个经皮质植入物在双侧股骨。在术后3、4和6周对植入物进行机械和组织学评估。进行机械推出测试，以确定界面附着强度和刚度。组织学切片评估界面组织特征、骨附着百分比和界面推出失败模式。统计分析表明，RA涂层显著提高了光滑热解碳植入体的界面抗剪强度和刚度。与光滑的表面纹理相比，沟槽表面纹理提高了机械附着强度，并且不受HA涂层应用的影响。组织学评估显示大量的直接种植体与骨的结合，很少或没有纤维组织存在。ha涂层种植体与未涂层种植体相比，具有光滑和纹理表面的直接骨贴合量显著增加。
{"title":"In vivo characterization of hydroxylapatite (HA) coated pyrolytic carbon implants","authors":"L.S. Popich, A. M. Rust-Dawicki, J. Klawitter, J. F. Kay, S. Cook","doi":"10.1109/SBEC.1995.514435","DOIUrl":"https://doi.org/10.1109/SBEC.1995.514435","url":null,"abstract":"Low-temperature isotropic (LTI) pyrolytic carbon implants (Carbon Implants, Austin, TX) with smooth and grooved surfaces were evaluated using the canine transcortical plug model. The implants were evaluated with and without a 50-75 /spl mu/m hydroxylapatite (HA) coating (Bio-Interfaces, Inc., San Diego, CA). Four adult mongrel dogs were used each receiving five transcortical implants bilaterally in the femur. The implants were evaluated mechanically and histologically at periods of 3, 4, and 6 weeks postoperatively. Mechanical pushout testing was performed to determine interface attachment strength and stiffness. Histologic sections were evaluated for interface tissue characterization, percent bone apposition, and mode of interface pushout failure. Statistical analysis revealed that RA coating significantly increased interface shear strength and stiffness of smooth pyrolytic carbon implants. A grooved surface texture resulted in improved mechanical attachment strength compared to smooth surface texture and was unaffected by the application of HA coating. Histologic evaluation showed a significant amount of direct implant-bone apposition with little or no fibrous tissue present. HA-coated implants had a significantly greater amount of direct bone apposition with both smooth and textured surfaces compared to uncoated implants.","PeriodicalId":332563,"journal":{"name":"Proceedings of the 1995 Fourteenth Southern Biomedical Engineering Conference","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114388260","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}
Pub Date : 1995-04-07DOI: 10.1109/SBEC.1995.514470
H. Medoff
Classical models of friction assume non-resilient surfaces, and are contact area independent. Pedestrian traction requirements remain controversial, as does the methodology of measuring coefficient of friction in situ. Athletic events, with severe maneuvers, can result in high traction requirements in order for the participants to successfully complete the activity. Typical outdoor athletic fields can be divided into natural and artificial surfaces, each with its own peculiar traction behavior when in contact with different athletic shoe outsoles. Friction testing devices, for use with athletic shoes and playing surfaces have been developed. However, traction requirements and appropriate test protocols have not been standardized.
{"title":"Problems in defining and measuring friction on natural and artificial playing surfaces","authors":"H. Medoff","doi":"10.1109/SBEC.1995.514470","DOIUrl":"https://doi.org/10.1109/SBEC.1995.514470","url":null,"abstract":"Classical models of friction assume non-resilient surfaces, and are contact area independent. Pedestrian traction requirements remain controversial, as does the methodology of measuring coefficient of friction in situ. Athletic events, with severe maneuvers, can result in high traction requirements in order for the participants to successfully complete the activity. Typical outdoor athletic fields can be divided into natural and artificial surfaces, each with its own peculiar traction behavior when in contact with different athletic shoe outsoles. Friction testing devices, for use with athletic shoes and playing surfaces have been developed. However, traction requirements and appropriate test protocols have not been standardized.","PeriodicalId":332563,"journal":{"name":"Proceedings of the 1995 Fourteenth Southern Biomedical Engineering Conference","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116183162","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}
Pub Date : 1995-04-07DOI: 10.1109/SBEC.1995.514484
K. Ju, T. Kuwaki, M. Kumada, S. Onish, H. Yamazaki
This study deals with the power spectral analysis of arterial blood pressure fluctuations by using an autoregressive model in mice. The authors analyzed the frequency contents in arterial blood pressure variability by estimating their power spectrum and analyzed the relationship between each frequency component and the activity of autonomic nervous system.
{"title":"Power spectral analysis of arterial blood pressure variability in conscious mice","authors":"K. Ju, T. Kuwaki, M. Kumada, S. Onish, H. Yamazaki","doi":"10.1109/SBEC.1995.514484","DOIUrl":"https://doi.org/10.1109/SBEC.1995.514484","url":null,"abstract":"This study deals with the power spectral analysis of arterial blood pressure fluctuations by using an autoregressive model in mice. The authors analyzed the frequency contents in arterial blood pressure variability by estimating their power spectrum and analyzed the relationship between each frequency component and the activity of autonomic nervous system.","PeriodicalId":332563,"journal":{"name":"Proceedings of the 1995 Fourteenth Southern Biomedical Engineering Conference","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116321204","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}
Pub Date : 1995-04-07DOI: 10.1109/SBEC.1995.514487
M. Hasan, H. Ranu
A mathematical model is developed and it is used to simulate the microfracture of human bone due to repetitive loading (e.g. jumping). Results show that less than eight jumps are enough to create a microfracture of human bone.
{"title":"Lower extremity microfracture simulation in human bone","authors":"M. Hasan, H. Ranu","doi":"10.1109/SBEC.1995.514487","DOIUrl":"https://doi.org/10.1109/SBEC.1995.514487","url":null,"abstract":"A mathematical model is developed and it is used to simulate the microfracture of human bone due to repetitive loading (e.g. jumping). Results show that less than eight jumps are enough to create a microfracture of human bone.","PeriodicalId":332563,"journal":{"name":"Proceedings of the 1995 Fourteenth Southern Biomedical Engineering Conference","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124626181","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}
Pub Date : 1995-04-07DOI: 10.1109/SBEC.1995.514455
G. Peyman, J. Schulman, M.R. Neisman
Summary form only received as follows: The phagocytic uptake of several liposome compositions by human retinal pigment epithelial (RPE) cells in culture was examined. The endocytic uptake of different Iiposome preparations was quantitatively measured for RPE, RAW 264.7 and rabbit dermal fibroblasts. RAW 264.7 is a transformed macrophagic murine cell line used as a positive control while rabbit dermal fibrocytes are a cell line developed for in vivo animal models of PVR. Measurement of the internalization of a non-degradable radiolabeled cholesterol analog incorporated in the liposome bilayer was used to quantify the uptake of liposomes. Fluorescence microscopy was used to confirm the internalization of the vesicles. The composition of liposomes most avidly ingested by RPE most closely resembled shed rod outer segments (ROS). The most actively phagocytized liposomes like the ROS plasma membrane contained phosphatidylserine and lacked cholesterol. Additionally, a greater uptake of the large multiluminar vesicles ranging in size from 0.20 /spl mu/m to 2 /spl mu/m compared to smaller vesicles extruded through a 0.22 /spl mu/m filter demonstrated liposomal size influenced the uptake process. The larger vesicles were closer in size to naturally occurring ROS. Uptake by RPE was significantly lower than observed with RAW 264.7 cells, but greater than exhibited by rabbit dermal fibroblasts. These findings appear to have important implications regarding the use of liposomes as drug carriers for the treatment of proliferative vitreoretinopathy and the study of phagocytosis by RPE.
{"title":"Uptake of liposomes by human retinal pigment epithelial cells in culture","authors":"G. Peyman, J. Schulman, M.R. Neisman","doi":"10.1109/SBEC.1995.514455","DOIUrl":"https://doi.org/10.1109/SBEC.1995.514455","url":null,"abstract":"Summary form only received as follows: The phagocytic uptake of several liposome compositions by human retinal pigment epithelial (RPE) cells in culture was examined. The endocytic uptake of different Iiposome preparations was quantitatively measured for RPE, RAW 264.7 and rabbit dermal fibroblasts. RAW 264.7 is a transformed macrophagic murine cell line used as a positive control while rabbit dermal fibrocytes are a cell line developed for in vivo animal models of PVR. Measurement of the internalization of a non-degradable radiolabeled cholesterol analog incorporated in the liposome bilayer was used to quantify the uptake of liposomes. Fluorescence microscopy was used to confirm the internalization of the vesicles. The composition of liposomes most avidly ingested by RPE most closely resembled shed rod outer segments (ROS). The most actively phagocytized liposomes like the ROS plasma membrane contained phosphatidylserine and lacked cholesterol. Additionally, a greater uptake of the large multiluminar vesicles ranging in size from 0.20 /spl mu/m to 2 /spl mu/m compared to smaller vesicles extruded through a 0.22 /spl mu/m filter demonstrated liposomal size influenced the uptake process. The larger vesicles were closer in size to naturally occurring ROS. Uptake by RPE was significantly lower than observed with RAW 264.7 cells, but greater than exhibited by rabbit dermal fibroblasts. These findings appear to have important implications regarding the use of liposomes as drug carriers for the treatment of proliferative vitreoretinopathy and the study of phagocytosis by RPE.","PeriodicalId":332563,"journal":{"name":"Proceedings of the 1995 Fourteenth Southern Biomedical Engineering Conference","volume":"371 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124643102","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}
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