Figure 3 - uploaded by Stuart Gallagher
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Illustration by time-lapse image sequences showing cell events before and after the beginning of the division (time 0). The mother cell (number 17) is replaced by two other cells, one retaining the number 17 and the other taking the number 22.
Source publication
The aim of this study was to describe and analyze the regulation and spatio-temporal dynamics of melanocyte migration in vitro and its coupling to cell division and interaction with the matrix. The melanocyte lineage is particularly interesting because it is involved in both embryonic development and oncogenesis/metastasis (melanoma). Biological ex...
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Context 1
... custom division detector has been presented previously [ 8], but its use required interactive validation by an operator. In this study, divisions were detected manually, separately from the cell tracking process. The time of division was recorded along with the frame number at which two daughter cells could be first distinctly identified following a cell division. Information relating to cell division can be extracted from phase-contrast time-lapse video microscopy (Figure 3). The number of cells dividing during the experiment was validated by a human operator to prevent some of the problems encountered with indirect tracking approaches (see [8]). This validation was rapid and straightforward, due to the characteristic roundness and brightness of the dividing cells (Figure 3). Before the division, the mother cell dramatically decreases its area and appears as a small bright disk. At the time of division, the daughter cells are spheres and appear to ...
Context 2
... custom division detector has been presented previously [ 8], but its use required interactive validation by an operator. In this study, divisions were detected manually, separately from the cell tracking process. The time of division was recorded along with the frame number at which two daughter cells could be first distinctly identified following a cell division. Information relating to cell division can be extracted from phase-contrast time-lapse video microscopy (Figure 3). The number of cells dividing during the experiment was validated by a human operator to prevent some of the problems encountered with indirect tracking approaches (see [8]). This validation was rapid and straightforward, due to the characteristic roundness and brightness of the dividing cells (Figure 3). Before the division, the mother cell dramatically decreases its area and appears as a small bright disk. At the time of division, the daughter cells are spheres and appear to ...
Similar publications
Mitosis detection poses a major challenge in cell tracking as mitoses are crucial events in the construction of genealogical trees. Making use of typical mitotic patterns that can be seen in phase contrast images of time lapse experiments, we propose a new benchmark data set CeTReS.B-MI consisting of mitotic and non-mitotic cells from the publicly...
The aim of this paper is to detail the development of a novel tracking framework that is able to extract the cell motility indicators and to determine the cellular division (mitosis) events in large time-lapse phase-contrast image sequences. To address the challenges induced by nonstructured (random) motion, cellular agglomeration, and cellular mit...
Phase contrast time-lapse microscopy is a non-destructive technique that generates large volumes of image-based information to quantify the behaviour of individual cells or cell populations. To guide the development of algorithms for computer-aided cell tracking and analysis, 48 time-lapse image sequences, each spanning approximately 3.5 days, were...
The analysis of time lapse data becomes a more and more important tool in (stem) cell biology, as this method enables a marker free analysis of cell populations over time and allows for the reconstruction of genealogical trees; these information can help to understand the mechanisms behind cell proliferation and differentiation. However, the crucia...
Citations
... Te length of the dendrites of melanocytes is determined by the number of surrounding keratinocytes. Ticker periodontal phenotypes exhibit greater length and number of melanocyte dendrites for stimulating faster rates of repigmentation [7,8]. ...
Harmony between facial complexion and gingival health goes hand in hand. Gingival depigmentation is an aesthetic correction of hyperactive melanocytes in gingival tissues that lead to hyperpigmentation. Current study compares depigmentation, pain scores, and itching with scalpel technique and nonsurgical intramucosal Vitamin C injection. 30 individuals in the age range of 18–40 years conscious of dark gums were randomly allocated to test and control group by lottery method. Thorough Phase I therapy was performed one week before the procedure. Area and intensity of depigmentation were evaluated preoperatively and postoperatively; pain score, itching, and repigmentation percentage were the postoperative parameters. After 24 hrs, test group showed significantly lesser VAS score for pain as compared to control group. There was no statistically significant difference in preoperative area of pigmentation between the test and control group ( p = 0.936 ). Postoperatively also, there was no statistically significant difference in area of pigmentation between the test and control group ( p = 0.932 ). For comparing area of pigmentation, an independent t-test was applied and Mann–Whitney test was used for differentiating the intensity of pigmentation, repigmentation, and VAS score between the groups. The study concluded that Vitamin C mesotherapy and scalpel technique showed comparable results in reduction of areas and intensity of gingival hyperpigmentation.
... Melanin could be delivered to the surrounding cells in the form of melanosomes. The thicker the gingival biotype is, the longer and higher the number of the menlanocyte's dendrites which mirrors the role of keratinocytes in stimulating melanogenesis [12,13] (Kippenberger et al., 1998 andLetort et al., 2010). ...
... Melanin could be delivered to the surrounding cells in the form of melanosomes. The thicker the gingival biotype is, the longer and higher the number of the menlanocyte's dendrites which mirrors the role of keratinocytes in stimulating melanogenesis [12,13] (Kippenberger et al., 1998 andLetort et al., 2010). ...
... Calcium deficiency causes failure of melanocytes to perform cellular adhesion to keratinocytes as calcium is essential to form cadherins [12,14] (Kippenberger et al., 1998 andTolleson, 2005). Adhesion to keratinocytes is important stimulator to melanocytes in order to produce melanin, format dendrites and transfer the produced melanin to neighboring cells [12,13] Therefore, the aim of the present study is to compare the clinical efficiency of the non-surgical intraepidermal injection of vitamin C in comparison to the gold standard surgical technique (scalpel technique) for gingival depigmentation. ...
Objective
The purpose of the current study is to evaluate the efficacy of intra-epidermal vitamin C injection in comparison to the conventional surgical technique in order to manage patients with gingival hyperpigmentation.
Design
Thirty patients were enrolled seeking for gingival depigmentation with mild to severe hyperpigmented gingival tissues. Clinical evaluation was performed pre and post-operatively. Double evaluation of the depigmenting effect was performed using two different color assessment indices (Takashi and Kumar indices). The pain and itching grades were reported using VAS scale.
Results
at baseline and 9 months, there was no statistical significant difference between both groups in index 1 and 2. At one month, statistical significant difference was reported in index 1 (p value = 0.003) and index 2 (p value = 0.002). Regarding pain score, statistical significant reduction in scores starting from day 1 (0.004), day 2 (0.0001) to 7 days (0.0015). Both surgical and non-surgical techniques revealed nearly equivalent results. Although non-surgical technique is less traumatic, it has several disadvantages such as time consumption - at least four weeks to achieve homogenous gingival color and needs tactile sensation. In addition, critical zones for injection have to be avoided.
Conclusions
The current study examines the points of strength and weakness of both techniques in depth. The surgical technique is considered as the gold standard for management of gingival hyperpigmentation. The usage of vitamin C injection for depigmentation showed comparative results in comparison to the conventional technique. Furthermore, the usage of vitamin C could provide a long term stability of the gingival color if used after the surgical procedure. Finally, we suggest that using both techniques has to be pre-determined according to the clinical examination and the patient's desire. Further researches are recommended to study the efficacy of using booster doses for long term color stability.
... We previously validated the automated cell tracking algorithm by comparing this method for in vitro analysis of murine melanocytes migration with results generated manually by human experts [12]. Here, we focus on different variables that can be retrieved using this software, and the advantages of Java-based software for biologists who are not familiar with computer programming. ...
Cell migration is a key biological process with a role in both physiological and pathological conditions. Locomotion of cells during embryonic development is essential for their correct positioning in the organism; immune cells have to migrate and circulate in response to injury. Failure of cells to migrate or an inappropriate acquisition of migratory capacities can result in severe defects such as altered pigmentation, skull and limb abnormalities during development, and defective wound repair, immunosuppression or tumor dissemination. The ability to accurately analyze and quantify cell migration is important for our understanding of development, homeostasis and disease. In vitro cell tracking experiments, using primary or established cell cultures, are often used to study migration as cells can quickly and easily be genetically or chemically manipulated. Images of the cells are acquired at regular time intervals over several hours using microscopes equipped with CCD camera. The locations (x,y,t) of each cell on the recorded sequence of frames then need to be tracked. Manual computer-assisted tracking is the traditional method for analyzing the migratory behavior of cells. However, this processing is extremely tedious and time-consuming. Most existing tracking algorithms require experience in programming languages that are unfamiliar to most biologists. We therefore developed an automated cell tracking program, written in Java, which uses a mean-shift algorithm and ImageJ as a library. iTrack4U is a user-friendly software. Compared to manual tracking, it saves considerable amount of time to generate and analyze the variables characterizing cell migration, since they are automatically computed with iTrack4U. Another major interest of iTrack4U is the standardization and the lack of inter-experimenter differences. Finally, iTrack4U is adapted for phase contrast and fluorescent cells.
... Evolution of this population can be described by Eq. (1) with the function F (u) given by formula (3) with n = 1. Random cell motion can be related to cell division [18] or to other mechanisms [76]. Cell proliferation is proportional to cell density multiplied by (1 − u). ...
The theory of reaction–diffusion waves begins in the 1930s with the works in population dynamics, combustion theory and chemical kinetics. At the present time, it is a well developed area of research which includes qualitative properties of travelling waves for the scalar reaction–diffusion equation and for system of equations, complex nonlinear dynamics, numerous applications in physics, chemistry, biology, medicine. This paper reviews biological applications of reaction–diffusion waves.
