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In vivo studies on leukoemboli formation—An intravital microscopic analysis
228
Abstracts
STRUCTURAL-.MECHANICAL
INDICATORS
OF LIMB
DAVID B. BURR and MITCHELL B. SCHAFFLER (Departments Virginia University, Morgantown,
SPECIALIZATION
IN PRIMATES
of Anatomy and Orthopedic WV 26506. U.S.A.)
Surgery, West
The objective of this study was to examine functional differentiation of the extremities using a structural analysis of the femur and humerus from primates representing a wide spectrum of habitual locomotor activities. Least squares regression analysis of average humeral and femoral bending rigidity on body weight, and comparison of slopes, were used to assess relative usage of the limbs in weight bearing and propulsion in four species of primates with different locomotor capabilities. The results of the study indicated that average bending rigidities of humerus and femur reflect forelimb-hindlimb functional dilferentiation in primates. Deviations of average bending rigidity from expected geometric similarity suggest functional variations from typical primate quadrupedalism. Moreover, the ratio of humerat to femoral bending rigidity identifies trends for hindlimb or forelimb dominance in locomotion.
MECHANICAL
BEHAVIOR
OF FETAL
DURA MATER TENSION
IN AXISYMMETRIC
BIAXIAL
D. I. BYLSKI (Biomechanics. Trauma, and Sports Medicine Laboratory, The University of Michigan, Ann Arbor, MI 48109, U.S.A.) T. .I. KRIEWALL (Surgical Products Division, 3M Company, 270-2A-10 3M Center, St. Paul, MN 55144, U.S.A.) N. AKKAS (Department of Civil Engineering, Middle East Technical University, Ankara, Turkey) J. W. MELVIN (Department of Mechanical Engineering, The University of Michigan, Ann Arbor, MI 48109, U.S.A.) The mechanical response of fetal dura mater was investigated using two different biaxial tension tests. The inflation test has been proposed and utilized for material identification of membranous soft tissue. A second biaxial tension test was specially designed to simulate the constraints imposed by the cranial bones on the dura mater, which forms the connections between the bones. The experimental stiffness results were compared to analytic results obtained from two published strain energy functions, one defined by Mooney and Rivlin, and the other by Skalak, Tozeren, Zarda, and Chien. For both experiments, the latter strain energy relations fit the test results consistently well.
IN I’lYO
STUDIES
ON LEUKOEMBOLI
FORMATION-AN ANALYSIS
INTRAVITAL
MICROSCOPIC
ANTHONY T. W. CHEUNG, MICHAEL E. MILLER, ERIN M. WALSH and RICHARD M. DONOVAN (School of Medicine and California Primate Research Center, University of California at Davis) A prototype intravital microscope was designed and constructed for the documentation and quantification of in rim movement and complement-mediated aggregation (leukoemboli formation) of leukocytes in the mesenteric microvasculature of laboratory rats. Briefly, Sprague-Dawley white rats were set up for intravital manipulation and microvascular documentation. Fluorescein-labeled leukocytes previously prepared before experimentation were intravenously injected into the rats. With epi-monochromatic irradiation set at line 488, the FITC-labeled leukocytes were activated to fluoresce and their flow and movement characteristics were documented (videotaped) with a SIT camera. The rate of movement, optical density, size ofeach fluorescent cell/particle and interaction with vessel wall were determined and quantified later by computer-assisted and manual analysis. Synthetic chemotactic peptides (FMLP) and endotoxin-activated serum (mostly C5a complex) were injected into separate animals and the effect of the injections on the functional and behavioral characteristics of the leukocytes and the resulting leukoemboli formation were videotaped for analysis. The videotapes were later digitized and quantified for morphometric and pathological characteristics by a micro-image-processing procedure.
FATIGUE
INDUCED
CHANGES IN STIFFNESS OF THE FLEXOR POLLICUS HUMAN SUBJECTS WITH INTACT REFLEXES
LONGUS
IN
PATRICK E. CRAGOand STEVE V. ZACHARKIW ( Departments of Biomedical Engineering and Orthopaedic Surgery, Case Western Reserve University, Cleveland, OH 44106, U.S.A.) The hypothesis that reflexes from muscle length and force receptors regulate the stiffness of contracting muscle was tested by comparing stiffness before and after internal disturbances in muscle gain induced by fatiguing
Abstracts
STRUCTURAL-.MECHANICAL
INDICATORS
OF LIMB
DAVID B. BURR and MITCHELL B. SCHAFFLER (Departments Virginia University, Morgantown,
SPECIALIZATION
IN PRIMATES
of Anatomy and Orthopedic WV 26506. U.S.A.)
Surgery, West
The objective of this study was to examine functional differentiation of the extremities using a structural analysis of the femur and humerus from primates representing a wide spectrum of habitual locomotor activities. Least squares regression analysis of average humeral and femoral bending rigidity on body weight, and comparison of slopes, were used to assess relative usage of the limbs in weight bearing and propulsion in four species of primates with different locomotor capabilities. The results of the study indicated that average bending rigidities of humerus and femur reflect forelimb-hindlimb functional dilferentiation in primates. Deviations of average bending rigidity from expected geometric similarity suggest functional variations from typical primate quadrupedalism. Moreover, the ratio of humerat to femoral bending rigidity identifies trends for hindlimb or forelimb dominance in locomotion.
MECHANICAL
BEHAVIOR
OF FETAL
DURA MATER TENSION
IN AXISYMMETRIC
BIAXIAL
D. I. BYLSKI (Biomechanics. Trauma, and Sports Medicine Laboratory, The University of Michigan, Ann Arbor, MI 48109, U.S.A.) T. .I. KRIEWALL (Surgical Products Division, 3M Company, 270-2A-10 3M Center, St. Paul, MN 55144, U.S.A.) N. AKKAS (Department of Civil Engineering, Middle East Technical University, Ankara, Turkey) J. W. MELVIN (Department of Mechanical Engineering, The University of Michigan, Ann Arbor, MI 48109, U.S.A.) The mechanical response of fetal dura mater was investigated using two different biaxial tension tests. The inflation test has been proposed and utilized for material identification of membranous soft tissue. A second biaxial tension test was specially designed to simulate the constraints imposed by the cranial bones on the dura mater, which forms the connections between the bones. The experimental stiffness results were compared to analytic results obtained from two published strain energy functions, one defined by Mooney and Rivlin, and the other by Skalak, Tozeren, Zarda, and Chien. For both experiments, the latter strain energy relations fit the test results consistently well.
IN I’lYO
STUDIES
ON LEUKOEMBOLI
FORMATION-AN ANALYSIS
INTRAVITAL
MICROSCOPIC
ANTHONY T. W. CHEUNG, MICHAEL E. MILLER, ERIN M. WALSH and RICHARD M. DONOVAN (School of Medicine and California Primate Research Center, University of California at Davis) A prototype intravital microscope was designed and constructed for the documentation and quantification of in rim movement and complement-mediated aggregation (leukoemboli formation) of leukocytes in the mesenteric microvasculature of laboratory rats. Briefly, Sprague-Dawley white rats were set up for intravital manipulation and microvascular documentation. Fluorescein-labeled leukocytes previously prepared before experimentation were intravenously injected into the rats. With epi-monochromatic irradiation set at line 488, the FITC-labeled leukocytes were activated to fluoresce and their flow and movement characteristics were documented (videotaped) with a SIT camera. The rate of movement, optical density, size ofeach fluorescent cell/particle and interaction with vessel wall were determined and quantified later by computer-assisted and manual analysis. Synthetic chemotactic peptides (FMLP) and endotoxin-activated serum (mostly C5a complex) were injected into separate animals and the effect of the injections on the functional and behavioral characteristics of the leukocytes and the resulting leukoemboli formation were videotaped for analysis. The videotapes were later digitized and quantified for morphometric and pathological characteristics by a micro-image-processing procedure.
FATIGUE
INDUCED
CHANGES IN STIFFNESS OF THE FLEXOR POLLICUS HUMAN SUBJECTS WITH INTACT REFLEXES
LONGUS
IN
PATRICK E. CRAGOand STEVE V. ZACHARKIW ( Departments of Biomedical Engineering and Orthopaedic Surgery, Case Western Reserve University, Cleveland, OH 44106, U.S.A.) The hypothesis that reflexes from muscle length and force receptors regulate the stiffness of contracting muscle was tested by comparing stiffness before and after internal disturbances in muscle gain induced by fatiguing