scholarly journals Constructing a Computer Model of the Human Eye Based on Tissue Slice Images

2010 ◽  
Vol 2010 ◽  
pp. 1-10 ◽  
Author(s):  
Peishan Dai ◽  
Boliang Wang ◽  
Chunbo Bao ◽  
Ying Ju
Keyword(s):  
Computer Model ◽  
Geometric Model ◽  
Three Dimensional ◽  
Tissue Slice ◽  
Central Axis ◽  
Virtual Surgery ◽  
Three Dimensional Model ◽  
Human Eye ◽  
Eye Tissues

Computer simulation of the biomechanical and biological heat transfer in ophthalmology greatly relies on having a reliable computer model of the human eye. This paper proposes a novel method on the construction of a geometric model of the human eye based on tissue slice images. Slice images were obtained from an in vitro Chinese human eye through an embryo specimen processing methods. A level set algorithm was used to extract contour points of eye tissues while a principle component analysis was used to detect the central axis of the image. The two-dimensional contour was rotated around the central axis to obtain a three-dimensional model of the human eye. Refined geometric models of the cornea, sclera, iris, lens, vitreous, and other eye tissues were then constructed with their position and ratio relationships kept intact. A preliminary study of eye tissue deformation in eye virtual surgery was simulated by a mass-spring model based on the computer models developed.

6-DOF Haptic Interface for Neurosurgical Simulation System

1999 ◽  
Author(s):  
Takeo Asano ◽  
Hiroshi Matsuzaki ◽  
Akito Saito ◽  
Yukihiko Furuhashi ◽  
Yuichiro Akatsuka ◽  
...  
Keyword(s):  
Minimally Invasive ◽  
Three Dimensional ◽  
Image Data ◽  
Simulation System ◽  
Haptic Interface ◽  
Virtual Object ◽  
Virtual Surgery ◽  
Surface Rendering ◽  
Three Dimensional Model ◽  
Head Surface

Abstract Practical use of medical simulation system with virtual reality technology is expected because of the learning of the operation procedure. We have therefore developed a neurosurgical simulation system for minimally invasive surgery. Our system is composed of PC and one or two haptic interfaces. Operator can pick up the region of interest to specify the disease portion from DICOM format image data, then three-dimensional model have made by volume and surface rendering with this data. In the next step, system estimates and indicates on CRT the minimally invasive path from the head surface to the disease target that was picked up beforehand by this system which retains healthy human’s three-dimensional atlas data. Finally, the operator can perform a virtual surgery operation by the haptic interface that has been connected to PC, and can cut off an exact or approximate portion of the disease. The operator can feel the resistance from this virtual object. This operation process can be recorded for medical doctors to review later.

Inhibitory effect of resveratrol on the growth and angiogenesis of human endometrial tissue in an In Vitro three-dimensional model of endometriosis

2020 ◽  
Vol 20 (4) ◽  
pp. 484-490
Author(s):  
Mohammad Rasool Khazaei ◽  
Zahra Rashidi ◽  
Farzaneh Chobsaz ◽  
Elham Niromand ◽  
Mozafar Khazaei
Keyword(s):  
Three Dimensional ◽  
Inhibitory Effect ◽  
Endometrial Tissue ◽  
Dimensional Model ◽  
Three Dimensional Model

Three-Dimensional Model of the Human Eye-Head Saccadic System

1997 ◽  
Vol 77 (2) ◽  
pp. 654-666 ◽  
Author(s):  
Douglas Tweed
Keyword(s):  
Three Dimensional ◽  
Head Movements ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Gaze Shifts ◽  
One Dimensional ◽  
Human Eye ◽  
Saccadic System ◽  
Listing's Law ◽  
Listing’S Law

Tweed, Douglas. Three-dimensional model of the human eye-head saccadic system. J. Neurophysiol. 77: 654–666, 1997. Current theories of eye-head gaze shifts deal only with one-dimensional motion, and do not touch on three-dimensional (3-D) issues such as curvature and Donders' laws. I show that recent 3-D data can be explained by a model based on ideas that are well established from one-dimensional studies, with just one new assumption: that the eye is driven toward a 3-D orientation in space that has been chosen so that Listing's law of the eye in head will hold when the eye-head movement is complete. As in previous, one-dimensional models, the eye and head are feedback-guided and the commands specifying desired eye position eye pass through a neural “saturation” so as to stay within the effective oculomotor range. The model correctly predicts the complex, 3-D trajectories of the head, eye in space, and eye in head in a variety of saccade tasks. And when it moves repeatedly to the same target, varying the contributions of eye and head, the model lands in different eye-in-space positions, but these positions differ only in their cyclotorsion about the line of sight, so they all point that line at the target—a behavior also seen in real eye-head saccades. Between movements the model obeys Listing's law of the eye in head and Donders' law of the head on torso, but during certain gaze shifts involving large torsional head movements, it shows marked, 8° deviations from Listing's law. These deviations are the most important untested predictions of the theory. Their experimental refutation would sink the model, whereas confirmation would strongly support its central claim that the eye moves toward a 3-D position in space chosen to obey Listing's law and, therefore, that a Listing operator exists upstream from the eye pulse generator.

scholarly journals Apicomplexan co-infections impair with phagocytic activity in avian macrophages

2020 ◽  
Vol 119 (12) ◽  
pp. 4159-4168
Author(s):  
Runhui Zhang ◽  
Wanpeng Zheng ◽  
Arwid Daugschies ◽  
Berit Bangoura
Keyword(s):  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Three Dimensional Model ◽  
Host Interactions ◽  
Macrophage Phagocytosis ◽  
High Doses ◽  
Free Ranging

AbstractMixed infections of Toxoplasma gondii and Eimeria tenella are likely to occur frequently due to the high prevalence of both pathogens in free-ranging chickens. In this study, we investigated the co-occurrence of the two parasites in the same immune-competent host cell towards altered patterns of parasite-host interactions. Chicken blood monocyte–derived macrophages were co-infected with T. gondii RH tachyzoites and E. tenella Houghton sporozoites in vitro for 24 h. Through monitoring the uptake of pH-sensitive pHrodo™ Zymosan BioParticles (“Zymosan”) by macrophages, we created a three-dimensional model and to analyze quantitatively phagocytosis using confocal laser scanning microscopy. Assessments of parasite populations were performed by qPCR at 2, 6, 12, and 24 h post-infection (hpi). At 6 hpi, phagocytosis was inhibited in the E. tenella–infected cultures while no inhibition of phagocytosis was observed due to T. gondii. Phagocytosis activity revealed more complex interactions during co-infection. At 12 and 24 hpi, phagocytosis response to “Zymosan” was distinctly weaker in co-infected cells than in all other groups except for cells mono-infected with high doses of E. tenella at 24 hpi. By qPCR, significantly reduced numbers of both intracellular parasites were recorded (10-fold) in all infected groups at 2 hpi. At 12 hpi, the T. gondii population reached lowest values but dramatically increased by 24 hpi. Our data confirm that macrophage phagocytosis is involved in the control of invasion by apicomplexan parasites in chicken which particularly applies to E. tenella infection and it was able to be altered by the co-existing parasites.

scholarly journals Identification of Novel Recognition Motifs and Regulatory Targets for the Yeast Actin-regulating Kinase Prk1p

2003 ◽  
Vol 14 (12) ◽  
pp. 4871-4884 ◽  
Author(s):  
Bo Huang ◽  
Guisheng Zeng ◽  
Alvin Y.J. Ng ◽  
Mingjie Cai
Keyword(s):  
Actin Cytoskeleton ◽  
Phosphorylation Site ◽  
Three Dimensional ◽  
Kinase Domain ◽  
Yeast Genome ◽  
Three Dimensional Model ◽  
Recognition Sequence ◽  
Yeast Saccharomyces Cerevisiae

Prk1p is a serine/threonine kinase involved in the regulation of the actin cytoskeleton organization in the yeast Saccharomyces cerevisiae. Previously, we have identified LxxQxTG as the phosphorylation site of Prk1p. In this report, the recognition sequence for Prk1p is investigated more thoroughly. It is found that the presence of a hydrophobic residue at the position of P-5 is necessary for Prk1p phosphorylation and L, I, V, and M are all able to confer the phosphorylation at various efficiencies. The residue flexibility at P-2 has also been identified to include Q, N, T, and S. A homology-based three-dimensional model of the kinase domain of Prk1p provided some structural interpretations for these substrate specificities. The characterization of the [L/I/V/M]xx[Q/N/T/S]xTG motif led to the identification of a spectrum of potential targets for Prk1p from yeast genome. One of them, Scd5p, which contains three LxxTxTG motifs and is previously known to be important for endocytosis and actin organization, has been chosen to demonstrate its relationship with Prk1p. Phosphorylation of Scd5p by Prk1p at the three LxxTxTG motifs could be detected in vitro and in vivo, and deletion of PRK1 suppressed the defects in actin cytoskeleton and endocytosis in one of the scd5 mutants. These results allowed us to conclude that Scd5p is likely another regulatory target of Prk1p.

scholarly journals Cleavage targets and the D-arginine-based inhibitors of the West Nile virus NS3 processing proteinase

2005 ◽  
Vol 393 (2) ◽  
pp. 503-511 ◽  
Author(s):  
Sergey A. Shiryaev ◽  
Boris I. Ratnikov ◽  
Alexei V. Chekanov ◽  
Sergey Sikora ◽  
Dmitri V. Rozanov ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Protein A ◽  
Three Dimensional ◽  
Proteolytic Processing ◽  
Three Dimensional Model ◽  
West Nile ◽  
Highly Active ◽  
Polyprotein Precursor ◽  
Global Threat

Mosquito-borne WNV (West Nile virus) is an emerging global threat. The NS3 proteinase, which is essential for the proteolytic processing of the viral polyprotein precursor, is a promising drug target. We have isolated and biochemically characterized the recombinant, highly active NS3 proteinase. We have determined that the NS3 proteinase functions in a manner that is distantly similar to furin in cleaving the peptide and protein substrates. We determined that aprotinin and D-arginine-based 9–12-mer peptides are potent inhibitors of WNV NS3 with Ki values of 26 nM and 1 nM respectively. Consistent with the essential role of NS3 activity in the life cycle of WNV and with the sensitivity of NS3 activity to the D-arginine-based peptides, we showed that nona-D-Arg-NH2 reduced WNV infection in primary neurons. We have also shown that myelin basic protein, a deficiency of which is linked to neurological abnormalities of the brain, is sensitive to NS3 proteolysis in vitro and therefore this protein represents a convenient test substrate for the studies of NS3. A three-dimensional model of WNV NS3 that we created may provide a structural guidance and a rationale for the subsequent design of fine-tuned inhibitors. Overall, our findings represent a foundation for in-depth mechanistic and structural studies as well as for the design of novel and efficient inhibitors of WNV NS3.

scholarly journals Mutagenesis and Molecular Modeling Reveal Three Key Extracellular Loops of the Membrane Receptor HasR That Are Involved in Hemophore HasA Binding

2007 ◽  
Vol 189 (14) ◽  
pp. 5379-5382 ◽  
Author(s):  
Clément Barjon ◽  
Karine Wecker ◽  
Nadia Izadi-Pruneyre ◽  
Philippe Delepelaire
Keyword(s):  
Molecular Modeling ◽  
Outer Membrane ◽  
Three Dimensional ◽  
Membrane Receptor ◽  
Dimensional Model ◽  
Outer Membrane Receptor ◽  
Three Dimensional Model ◽  
Extracellular Loops

ABSTRACT On the basis of the three-dimensional model of the heme/hemophore TonB-dependent outer membrane receptor HasR, mutants with six-residue deletions in the 11 putative extracellular loops were generated. Although all mutants continued to be active TonB-dependent heme transporters, mutations in three loops abolished hemophore HasA binding both in vivo and in vitro.

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