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A computer-assisted method for measuring cell movement
230
Abstracts
calculated for the multiple data sets. Only one pad resulted in a combination of significant t and nonsignificant r which caused it to be disqualified from further clinical use. Pads demonstrated high internal consistency and high multiple trial consistency with CVs ranging from 0.119 to 0.273 and 0.041 to 0.13, respectively.
SYSTEMATIC ERROR IN THREE-DIMENSIONAL COORDINATES WITHIN A LARGE OBJECT-SPACE WHEN USING THE DLT AND NLT METHODS OF THREE-DIMESSIONAL CINEMATOGRAPHY JES~~SDAPENA
(Biomechanics Laboratory, Department of Physical Education, Indiana University, Bloomington, IN 47405, U.S.A.)
Three-dimensional coordinates of 48 points of a 5 x 5 x 2.3 m grid were calculated from film data using three methods: (a) Direct Linear Transformation (DLT) with a triaxial control object (DLTT), dimensions = 1.77 x 1.67 x 1.90 m; (b) DLT with a cuboid control object (DLT,), dimensions = 1.67 x 1.67 x I.15 m; (c) NonLinear Transformation (NLT), cross spans = 1.10, segment length = 2.15 m. The error analysis included the calculation of the eigenvalues, or principal tension-compression values (maximum, minimum and intermediate), at each point of the grid. The averages of the eigenvalues were: 4.8 y0 (DLTT), 2.1% (DLTc), and 2.0% (NLT). The results indicated that the accuracy of the DLT method is similar to that ofthe NLT method when a cuboid control object is used, and inferior when a triaxial control object is used.
A COMPUTER-ASSISTED
METHOD
FOR MEASURING CELL MOVEMEKT RICHARD M. DONOVAN, ANTHONY T. W. CHEUNG, MICHAEL E. MILLER and ELLIOT GOLDSTEIN(School of Medicine and California Primate Research Centre, University of California at Dab-is) We have developed a computer-assisted method to quantify movement characteristics of individual cells. Videotapes ofcellular activity (taped under phase contrast microscopy) were digitized at a resolution of 240 x 320 x 8 bits using a Datacube analog to digital converter, interfaced with a LSI 1l/23 computer operating under RT1l/TSX. The digitized data were then used for computation of cell perimeter, area, optical density, position, speed and direction with the utilization ofcomputer programs written in FORTRAN and ASSEMBLY language. Our system can simultaneously trace up to 50 cells at time intervals as short as 10 s and can determine instantaneously and accurately the speed, direction and other movement and morphometric characteristics. The compatibility and reproducibility of measurements made with our computer-assisted system was tested by comparison with established manual measurements on neutrophil chemotaxis. A correlation coefficient of0.99 was obtained between the two methods. However, the computer-assisted method is much faster, less tedious, accurate and more objective than commonly-used manual methods.
TIME DOMAINE
VIBRATION ANALYSIS IN THE ASSESSMENT OF STABILITY IllTERNAL FIXATION OF TIBIAL FRACWRES
AFI-ER
J. A. FAIRCLOUGH,W. J. MIN-I’OWT-Czuz, I. G. MACKIEand L. D. M. NOKES (Cardiff Royal Infirmary, Cardiff, U.K.) The human tibia will transmit’ vibration along its length in response to an impulse at one end. Accelerometers positioned proximally and distally detect the vibration and can measure its magnitude. The ratio of the distal to the proximal measurements yields a measure (AF, the attenuation factor) of the attenuation of the vibration as it passes along the bone. Transmission of vibration does not occur across an interuption but can be restored if the interuption is bridged. We have used osteotomies in cadaver tibiae to simulate fractures, and have then fixed them with different plates put on in various fashions with the object of finding out if the level of vibration transmission can reflect the stability of the internal fixation. The models studied were: (1) unfixed osteotomy; (2) optimum fixation with 4.5 mm A0 plate and compression; (3) A0 plate (4.5 mm) fixation with a gap; (4) compression fixation with a l/3 tubular A0 plate. The results show that the unfixed osteotomy does not transmit vibration significantly, but that an optimum compression fixation with an adequate implant restores vibration transmission to normal. The gap fixed single plate model transmits vibration only slightly better than the unfixed osteotomy, but in contrast, the inadequate l/3 tubular implant fixed in compression increases transmission three-fold.
Abstracts
calculated for the multiple data sets. Only one pad resulted in a combination of significant t and nonsignificant r which caused it to be disqualified from further clinical use. Pads demonstrated high internal consistency and high multiple trial consistency with CVs ranging from 0.119 to 0.273 and 0.041 to 0.13, respectively.
SYSTEMATIC ERROR IN THREE-DIMENSIONAL COORDINATES WITHIN A LARGE OBJECT-SPACE WHEN USING THE DLT AND NLT METHODS OF THREE-DIMESSIONAL CINEMATOGRAPHY JES~~SDAPENA
(Biomechanics Laboratory, Department of Physical Education, Indiana University, Bloomington, IN 47405, U.S.A.)
Three-dimensional coordinates of 48 points of a 5 x 5 x 2.3 m grid were calculated from film data using three methods: (a) Direct Linear Transformation (DLT) with a triaxial control object (DLTT), dimensions = 1.77 x 1.67 x 1.90 m; (b) DLT with a cuboid control object (DLT,), dimensions = 1.67 x 1.67 x I.15 m; (c) NonLinear Transformation (NLT), cross spans = 1.10, segment length = 2.15 m. The error analysis included the calculation of the eigenvalues, or principal tension-compression values (maximum, minimum and intermediate), at each point of the grid. The averages of the eigenvalues were: 4.8 y0 (DLTT), 2.1% (DLTc), and 2.0% (NLT). The results indicated that the accuracy of the DLT method is similar to that ofthe NLT method when a cuboid control object is used, and inferior when a triaxial control object is used.
A COMPUTER-ASSISTED
METHOD
FOR MEASURING CELL MOVEMEKT RICHARD M. DONOVAN, ANTHONY T. W. CHEUNG, MICHAEL E. MILLER and ELLIOT GOLDSTEIN(School of Medicine and California Primate Research Centre, University of California at Dab-is) We have developed a computer-assisted method to quantify movement characteristics of individual cells. Videotapes ofcellular activity (taped under phase contrast microscopy) were digitized at a resolution of 240 x 320 x 8 bits using a Datacube analog to digital converter, interfaced with a LSI 1l/23 computer operating under RT1l/TSX. The digitized data were then used for computation of cell perimeter, area, optical density, position, speed and direction with the utilization ofcomputer programs written in FORTRAN and ASSEMBLY language. Our system can simultaneously trace up to 50 cells at time intervals as short as 10 s and can determine instantaneously and accurately the speed, direction and other movement and morphometric characteristics. The compatibility and reproducibility of measurements made with our computer-assisted system was tested by comparison with established manual measurements on neutrophil chemotaxis. A correlation coefficient of0.99 was obtained between the two methods. However, the computer-assisted method is much faster, less tedious, accurate and more objective than commonly-used manual methods.
TIME DOMAINE
VIBRATION ANALYSIS IN THE ASSESSMENT OF STABILITY IllTERNAL FIXATION OF TIBIAL FRACWRES
AFI-ER
J. A. FAIRCLOUGH,W. J. MIN-I’OWT-Czuz, I. G. MACKIEand L. D. M. NOKES (Cardiff Royal Infirmary, Cardiff, U.K.) The human tibia will transmit’ vibration along its length in response to an impulse at one end. Accelerometers positioned proximally and distally detect the vibration and can measure its magnitude. The ratio of the distal to the proximal measurements yields a measure (AF, the attenuation factor) of the attenuation of the vibration as it passes along the bone. Transmission of vibration does not occur across an interuption but can be restored if the interuption is bridged. We have used osteotomies in cadaver tibiae to simulate fractures, and have then fixed them with different plates put on in various fashions with the object of finding out if the level of vibration transmission can reflect the stability of the internal fixation. The models studied were: (1) unfixed osteotomy; (2) optimum fixation with 4.5 mm A0 plate and compression; (3) A0 plate (4.5 mm) fixation with a gap; (4) compression fixation with a l/3 tubular A0 plate. The results show that the unfixed osteotomy does not transmit vibration significantly, but that an optimum compression fixation with an adequate implant restores vibration transmission to normal. The gap fixed single plate model transmits vibration only slightly better than the unfixed osteotomy, but in contrast, the inadequate l/3 tubular implant fixed in compression increases transmission three-fold.