In vivo kinematic analysis of replaced hip during stationary cycling and computer simulation of optimal cup positioning against prosthetic impingement

This is the third of three papers [see also Mulquiney, Bubb and Kuchel (1999) Biochem. J. 342, 565-578; Mulquiney and Kuchel (1999) Biochem. J. 342, 579-594] for which the general goal was to explain the regulation and control of 2,3-bisphosphoglycerate (2,3-BPG) metabolism in human erythrocytes. 2,3-BPG is a major modulator of haemoglobin oxygen affinity and hence is vital in blood oxygen transport. A detailed mathematical model of erythrocyte metabolism was presented in the first two papers. The model was refined through an iterative loop of experiment and simulation and it was used to predict outcomes that are consistent with the metabolic behaviour of the erythrocyte under a wide variety of experimental and physiological conditions. For the present paper, the model was examined using computer simulation and Metabolic Control Analysis. The analysis yielded several new insights into the regulation and control of 2,3-BPG metabolism. Specifically it was found that: (1) the feedback inhibition of hexokinase and phosphofructokinase by 2,3-BPG are equally as important as the product inhibition of 2,3-BPG synthase in controlling the normal in vivo steady-state concentration of 2,3-BPG; (2) H+ and oxygen are effective regulators of 2,3-BPG concentration and that increases in 2,3-BPG concentrations are achieved with only small changes in glycolytic rate; (3) these two effectors exert most of their influence through hexokinase and phosphofructokinase; (4) flux through the 2,3-BPG shunt changes in absolute terms in response to different energy demands placed on the cell. This response of the 2,3-BPG shunt contributes an [ATP]-stabilizing effect. A ‘cost’ of this is that 2,3-BPG concentrations are very sensitive to the energy demand of the cell and; (5) the flux through the 2,3-BPG shunt does not change in response to different non-glycolytic demands for NADH.

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Knee motion symmetry was not restored in patients with unilateral bi-cruciate retaining total knee arthroplasty—in vivo three-dimensional kinematic analysis

International Orthopaedics ◽

10.1007/s00264-018-3986-8 ◽

2018 ◽

Vol 42 (12) ◽

pp. 2817-2823 ◽

Cited By ~ 10

Author(s):

Paul Arauz ◽

Yun Peng ◽

Young-Min Kwon

Keyword(s):

Total Knee Arthroplasty ◽

Knee Arthroplasty ◽

Kinematic Analysis ◽

Three Dimensional ◽

Knee Motion ◽

Cruciate Retaining ◽

Total Knee

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CO binding to hemoglobin and myoglobin in equilibrium with a gas phase of low PO2 value

Journal of Applied Physiology ◽

10.1152/jappl.1988.65.6.2513 ◽

1988 ◽

Vol 65 (6) ◽

pp. 2513-2517 ◽

Cited By ~ 2

Author(s):

A. Agostoni ◽

M. Perrella ◽

L. Sabbioneda ◽

U. Zoni

Keyword(s):

Computer Simulation ◽

Gas Phase ◽

Qualitative Agreement ◽

Significant Proportion ◽

In Vitro System

The aim of this paper was to measure the binding of CO to myoglobin and hemoglobin at various PO2 values. For this purpose we have studied an "in vitro" system made up of solutions of hemoglobin and myoglobin equilibrated in two connected tonometers with the same gas phase of various PO2 and PCO. The results indicate that a significant proportion of CO is released by hemoglobin and binds myoglobin at low PO2 values (approximately 2-3 Torr), in qualitative agreement with the predictions of a previous computer simulation of the "in vivo" system.

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In vivo kinematic analysis of patients with robotic‐assisted total hip arthroplasty during gait at 1‐year follow‐up

International Journal of Medical Robotics and Computer Assisted Surgery ◽

10.1002/rcs.2021 ◽

2019 ◽

Vol 15 (5) ◽

Cited By ~ 9

Author(s):

Yun Peng ◽

Paul Arauz ◽

Pooja Desai ◽

Ashlyn Byers ◽

Christian Klemt ◽

...

Keyword(s):

Total Hip Arthroplasty ◽

Hip Arthroplasty ◽

Kinematic Analysis ◽

Robotic Assisted ◽

Total Hip

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Computer simulation of neutrophil transit through the pulmonary capillary bed

Journal of Applied Physiology ◽

10.1152/jappl.1993.74.4.1647 ◽

1993 ◽

Vol 74 (4) ◽

pp. 1647-1652 ◽

Cited By ~ 9

Author(s):

C. C. Hanger ◽

W. W. Wagner ◽

S. J. Janke ◽

T. C. Lloyd ◽

R. L. Capen

Keyword(s):

Computer Simulation ◽

Computer Model ◽

Pulmonary Circulation ◽

Cell Deformation ◽

In Vivo Microscopy ◽

Pulmonary Capillaries ◽

Pulmonary Capillary ◽

Capillary Bed ◽

Diameter Distributions

One-half of the neutrophils that enter the pulmonary circulation become temporarily trapped in capillaries. The neutrophils that are impeded make complete stops between free-flowing movements. These observations, based on in vivo microscopy, suggest that pulmonary margination is caused by neutrophils being impeded at focal sites in the capillary bed. To investigate the frequency with which impeding sites had to occur in the pulmonary capillaries to trap one-half of the circulating neutrophils, we developed a computer model to simulate neutrophils encountering discrete obstructions in a capillary-like network. Surprisingly, if only 1% of the capillaries in the network acted as traps, one-half of the neutrophils stopped at least once. The trapping ability of a given percentage of obstructions was independent both of the geometry of the network was whether the obstructions occurred in the segments or junctions. To simulate neutrophil transit more realistically, both neutrophil and capillary diameters were randomly selected from published diameter distributions. Every neutrophil was trapped multiple times by this model, suggesting that cell deformation contributes importantly to neutrophil passage through the pulmonary capillary bed.

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Thermal Distribution of Ultrasound Waves in Prostate Tumor: Comparison of Computational Modeling with In Vivo Experiments

ISRN Biomathematics ◽

10.1155/2013/428659 ◽

2013 ◽

Vol 2013 ◽

pp. 1-4 ◽

Cited By ~ 6

Author(s):

Forough Jafarian Dehkordi ◽

Ali Shakeri-Zadeh ◽

Samideh Khoei ◽

Hossein Ghadiri ◽

Mohammad-Bagher Shiran

Keyword(s):

Computer Simulation ◽

Temperature Rise ◽

Temperature Increase ◽

Ultrasound Irradiation ◽

Prostate Tumor ◽

Great Promise ◽

Distribution Profile ◽

Thermal Distribution ◽

In Vivo Experiments

Ultrasound irradiation to a certain site of the body affects the efficacy of drug delivery through changes in the permeability of cell membrane. Temperature increase in irradiated area may be affected by frequency, intensity, period of ultrasound, and blood perfusion. The aim of present study is to use computer simulation and offer an appropriate model for thermal distribution profile in prostate tumor. Moreover, computer model was validated by in vivo experiments. Method. Computer simulation was performed with COMSOL software. Experiments were carried out on prostate tumor induced in nude mice (DU145 cell line originated from human prostate cancer) at frequency of 3 MHz and intensities of 0.3, 0.5, and 1 w/cm2 for 300 seconds. Results. Computer simulations showed a temperature rise of the tumor for the applied intensities of 0.3, 0.5 and 1 w/cm2 of 0.8, 0.9, and 1.1°C, respectively. The experimental data carried out at the same frequency demonstrated that temperature increase was 0.5, 0.9, and 1.4°C for the above intensities. It was noticed that temperature rise was very sharp for the first few seconds of ultrasound irradiation and then increased moderately. Conclusion. Obtained data holds great promise to develop a model which is able to predict temperature distribution profile in vivo condition.

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