| 1. |
- Lundh, Torbjörn, 1965, et al.
(författare)
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Cross- and triple-ratios of human body parts during development
- 2011
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Ingår i: Anatomical Record. - 1932-8494 .- 1932-8486. ; 294, s. 1360-1369
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Tidskriftsartikel (refereegranskat)abstract
- Recently developed landmark-based geometric morphometry has been used to depict the morphological development of organisms. In geometry,four landmarks can be mapped to any other four by Mo¨bius transformations,if the cross-ratio of the landmarks is invariant and vice versa. To geometrically analyze the morphological development of the human body,we examined the cross-ratio of three consecutive body parts that are segmented by four landmarks in their configuration. Moreover, we introduced the triple-ratio of five landmarks that segments four consecutive parts (e.g., the shoulder, upper arm, forearm, and hand) and examined their growth patterns. The cross- and triple-ratios of the upper limb andshoulder girdle in fetuses were constant when biomechanical landmarks were used, although the cross-ratio of the upper limb varied when anatomical landmarks were used. The cross-ratios of the lower limbs, trunk,and pelvic girdles in fetuses differed from their corresponding cross-ratiosin adults. These results suggest Mo¨bius growth in the fetal upper limb and shoulder girdle but not in the other body parts examined. However, the growth balance of the three contiguous body parts was represented by the developmental change in the cross-ratio. Therefore, the cross- andtriple-ratios may be applicable for simple but significant assessments of growth balance or proportion of the body parts. Anat Rec, 294:1360–1369, 2011.
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| 2. |
- Otani, Hiroki, et al.
(författare)
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Morphometric study on the characteristic external features of normal and abnormal human embryos
- 2008
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Ingår i: Congenit Anom Kyoto. - : Wiley. ; 48:1, s. 18-28
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Tidskriftsartikel (refereegranskat)abstract
- The embryonic period is characterized by organogenesis and accompanying dynamic changes in external features. The measurement of human embryos has been limited to whole body dimensions, such as crown-rump length. More detailed measurements would add quantitative information about these characteristic events and provide a better understanding of normal and abnormal embryonic development. In the present study, we defined axes, landmarks, and measurements for human embryos, and measured 250 externally normal human embryos at Carnegie stages 14-23 (6.5-29.3 mm in crown-rump length, approximately 5-8 weeks of estimated ovulation age) that were fixed in Bouin's solution and preserved in 10% formalin solution. The axes, landmarks, and measurements defined for human embryos are corresponding to those in human and primate fetuses. The whole body, head, face, and extremities were measured using a scale attached to a dissecting microscope. Axial length, head height plus ear-shoulder length plus trunk height, was designated as a new measurement of the whole body, which is comparable with crown-rump length. Approximate standards of these measurements were obtained. The ratios of some measurements to trunk height and between the different parts were also obtained, and several different developmental patterns were recognized. The reproducibility of each measurement was evaluated by measuring 50 specimens three times each at intervals of one or two months. As a pilot study for the application of the proposed measurements, 84 human embryos with external anomalies, including holoprosencephaly, anomalies of extremities, and pharyngeal arch anomalies, were measured using the same method, and a few tendencies characteristic to holoprosencephaly were noticed.
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| 3. |
- Rafiq, Ashiq, et al.
(författare)
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Mathematical analysis of mandibular morphogenesis by micro-CT-based mouse and alizarin red S-stained-based human studies during development
- 2012
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Ingår i: Anatomical Record. - : Wiley. - 1932-8494 .- 1932-8486. ; 295:2, s. 313-327
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Tidskriftsartikel (refereegranskat)abstract
- Prenatal development of the mandible is an important factor in its postnatal function. To examine quantitatively normal and abnormal developmental changes of the mandible, we here evaluated morphological changes in mineralizing mandibles by thin-plate spline (TPS) including bending energy (BE) and Procrustes distance (PD), and by Procrustes analyses including warp analysis, regression analysis, and discriminant function analysis. BE and PD were calculated from lateral views of the mandibles of mice or of human fetuses using scanned micro-computed tomography (CT) images or alizarin red S-stained specimens, respectively. BE and PD were compared (1) between different developmental stages, and further, to detect abnormalities in the data sets and to evaluate the deviation from normal development in mouse fetuses, (2) at embryonic day (E) 18.5 between the normal and deformed mandibles, the latter being caused by suturing the jaw at E15.5, (3) at E15.5 and E18.5 between normal and knockout mutant mice of receptor tyrosine kinase-like orphan receptor (Ror) 2. In mice, BE and PD were large during the prenatal period and small after postnatal day 3, suggesting that the mandibular shape changes rapidly during the prenatal and early postnatal periods. In humans, BE of the mandibles peaked at 16–19 weeks of gestation, suggesting the time-dependent change in the mandibular shape. TPS and Procrustes analyses statistically separated the abnormal mandibles of the sutured or Ror2 mutant mouse fetuses from the normal mandible. These results suggest that TPS and Procrustes analyses are useful for assessing the morphogenesis and deformity of the mandible.
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| 4. |
- Tamagawa, T., et al.
(författare)
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Correlation between musculoskeletal structure of the hand and primate locomotion: Morphometric and mechanical analysis in prehension using the cross- and triple-ratios
- 2020
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 15:5
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Tidskriftsartikel (refereegranskat)abstract
- Biometric ratios of the relative length of the rays in the hand have been analyzed between primate species in the light of their hand function or phylogeny. However, how relative lengths among phalanges are mechanically linked to the grasping function of primates with different locomotor behaviors remains unclear. To clarify this, we calculated cross and triple-ratios, which are related to the torque distribution, and the torque generation mode at different joint angles using the lengths of the phalanges and metacarpal bones in 52 primates belonging to 25 species. The torque exerted on the finger joint and traction force of the flexor tendons necessary for a cylindrical grip and a suspensory hand posture were calculated using the moment arm of flexor tendons measured on magnetic resonance images, and were compared among Hylobates spp., Ateles sp., and Papio hamadryas. Finally, the torques calculated from the model were validated by a mechanical study detecting the force exerted on the phalanx by pulling the digital flexor muscles during suspension in these three species. Canonical discriminant analysis of cross and triple-ratios classified primates almost in accordance with their current classification based on locomotor behavior. The traction force was markedly reduced with flexion of the MCP joint parallel to the torque in brachiating primates; this was notably lower in the terrestrial quadrupedal primates than in the arboreal primates at mild flexion. Our mechanical study supported these features in the torque and traction force generation efficiencies. Our results suggest that suspensory or terrestrial quadrupedal primates have hand structures that can exert more torque at a suspensory posture, or palmigrade and digitigrade locomotion, respectively. Furthermore, our study suggests availability of the cross and triple-ratios as one of the indicators to estimate the hand function from the skeletal structure.
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| 5. |
- Tapani, Sofia, 1982, et al.
(författare)
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Three dimensional mathematical modelling of pronuclei migration for the mouse
- 2009
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Ingår i: Stereology and Image Analysis. Ecs10: Proceeding of the 10th European Conference of ISS., (V.Capasso et al. Ed.), The MIRIAM Project Series. - 9788874883103 ; 4, s. 1-6
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Konferensbidrag (refereegranskat)abstract
- It is still an open question when the orientation of the embryonic-abembryonic axis of the mouse embryo is laid down. The two most explicit symmetry breaking events for the egg are the extrusion of the second polar body and the sperm entry. The main question addressed in this paper is what happens between the sperm entering the egg and fusion of the two pronuclei. Orientation of the apposing pronuclei probably plays a decisive role in the polarity of the developing embryo. In order to shed some lights on this intriguing question, a mathematical model that describes the pronuclei dynamics have been constructed in the form of a stochastic differential equation. The model concerns pronuclei migration from the time of the sperm entry to the fusion and spatial orientation of this fusion. The methodology consists of using stacks of confocal microscopy time-lapse images of the pronuclei migration together with statistical methods to identify realistic parameters in the model. Given different angles between the sperm entry and the position of the second polar body, the final model is then used to produce distributions of orientations of the meeting positions between the pronuclei. However, the main result is the suggested model itself which describes the main features of the migration. The fitted model is based on two forces of attraction. Migration is directed towards the centre but also towards the other pronucleus. Parameter values corresponding to the size of these forces are estimated from data of both eggs treated with a microtubule inhibitor and untreated eggs. Simulations from the model with the different model parameters are accomplished and distributions of meeting positions are plotted. These simulated distributions could for instance be used as initial value distributions for future models of egg cleavage.
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