Cell movements in morphogenesis of hydroid polypes

Development ◽  
1972 ◽  
Vol 27 (2) ◽  
pp. 317-337
Author(s):  
L. V. Beloussov ◽  
L. A. Badenko ◽  
A. L. Katchurin ◽  
L. F. Kurilo

1. Growth, morphogenesis and cell movements were studied in Obelia loveni, O. geniculata and Dynamena pumila with the use of time-lapse cinematography, visual observations of vitally stained objects and by histological techniques. 2. Growth pulsations with the period around 14min and the amplitude around 15 μm exist in Dynamena pumila and with the period 5–8 min and amplitude up to 5 μm in Obelia loveni. It was demonstrated that the rhythm of growth pulsations does not coincide with the rhythm of periodical contractions of the proximal part of coenosarc. 3. The distalwards movements of individual cells in the ectoderm of growing stems and hydranth rudiments are described. A considerable variability in the rates of movements of ectodermal cells has been demonstrated. 4. Different kinds of cell reorientations in developing rudiments are described. As a rule, they precede the alterations of growth directions or of rudiment shapes. 5. The mechanisms involved in deformations of epithelial layers are discussed. 6. The possibility of the existence of passive, elastico-plastic structures in the deforming epithelial sheets is suggested.

2014 ◽  
Vol 56 (1) ◽  
pp. 587-597 ◽  
Author(s):  
J. A. Majdi ◽  
H. Qian ◽  
Y. Li ◽  
R. J. Langsner ◽  
K. I. Shea ◽  
...  

1992 ◽  
Vol 38 (129) ◽  
pp. 257-265 ◽  
Author(s):  
W.D. Harrison ◽  
K.A. Echelmeyer ◽  
D.M. Cosgrove ◽  
C. F. Raymond

AbstractTwo practical problems in the use of time-lapse photography for the measurement of speed were encountered during the recent surge of West Fork Glacier in the central Alaska Range, Alaska, U.S.A. The first is severe rotational camera instability; we show how natural, unsurveyed features on the valley wall can be used to make the necessary corrections. The second problem is the computation of absolute speed when many different, unsurveyed glacier-surface features are used as targets. We give a method for connecting the data obtained from different targets, and for determining the scale using limited information obtained by surveying. Severe systematic errors can occur unless the angle between the axis of the lens and the direction of horizontal motion is determined.


Author(s):  
Walter F. Holmström ◽  
Elfed Morgan

The endogenous activity rhythm of the estuarine amphipod Corophium volutator has been studied by direct observation and with the use of time lapse photography. The rhythm persists under constant conditions having a free running period of between 12 and 13 h, and with activity maxima occurring during the early ebb. Freshly collected animals show a rhythm which is modulated on a semi-lunar basis, the activity maxima being attenuated during the neap tide periods, and the rhythm has also been found to vary in definition throughout the year. The activity pattern is most clearly denned in early summer and autumn, the population becoming arrhythmic during the winter months. The rhythm is relatively unaffected by the ambient light intensity and temperature of the recording conditions, and is evident in all post-natal stages of development. The possibility of mutual entrainment is discussed.


1968 ◽  
Vol 11 (3) ◽  
pp. 0409-0411
Author(s):  
W. H. Henson ◽  
Jr. ◽  
J. M. Bunn and G. A. Duncan

1998 ◽  
Vol 28 (5) ◽  
pp. 883-892 ◽  
Author(s):  
Chris D. Webb ◽  
Peter L. Graumann ◽  
Jason A. Kahana ◽  
Aurelio A. Teleman ◽  
Pamela A. Silver ◽  
...  

2020 ◽  
Vol 2020 (2) ◽  
Author(s):  
Susanna Apter ◽  
Thomas Ebner ◽  
Thomas Freour ◽  
Yves Guns ◽  
Borut Kovacic ◽  
...  

Abstract STUDY QUESTION What recommendations can be provided on the approach to and use of time-lapse technology (TLT) in an IVF laboratory? SUMMARY ANSWER The present ESHRE document provides 11 recommendations on how to introduce TLT in the IVF laboratory. WHAT IS KNOWN ALREADY Studies have been published on the use of TLT in clinical embryology. However, a systematic assessment of how to approach and introduce this technology is currently missing. STUDY DESIGN, SIZE, DURATION A working group of members of the Steering Committee of the ESHRE Special Interest Group in Embryology and selected ESHRE members was formed in order to write recommendations on the practical aspects of TLT for the IVF laboratory. PARTICIPANTS/MATERIALS, SETTING, METHODS The working group included 11 members of different nationalities with internationally recognized experience in clinical embryology and basic science embryology, in addition to TLT. This document is developed according to the manual for development of ESHRE recommendations for good practice. Where possible, the statements are supported by studies retrieved from a PUBMED literature search on ‘time-lapse’ and ART. MAIN RESULTS AND THE ROLE OF CHANCE A clear clinical benefit of the use of TLT, i.e. an increase in IVF success rates, remains to be proven. Meanwhile, TLT systems are being introduced in IVF laboratories. The working group listed 11 recommendations on what to do before introducing TLT in the lab. These statements include an assessment of the pros and cons of acquiring a TLT system, selection of relevant morphokinetic parameters, selection of an appropriate TLT system with technical and customer support, development of an internal checklist and education of staff. All these aspects are explained further here, based on the current literature and expert opinion. LIMITATIONS, REASONS FOR CAUTION Owing to the limited evidence available, recommendations are mostly based on clinical and technical expertise. The paper provides technical advice, but leaves any decision on whether or not to use TLT to the individual centres. WIDER IMPLICATIONS OF THE FINDINGS This document is expected to have a significant impact on future developments of clinical embryology, considering the increasing role and impact of TLT. STUDY FUNDING/COMPETING INTEREST(S) The meetings of the working group were funded by ESHRE. S.A. declares participation in the Nordic Embryology Academic Team with meetings sponsored by Gedeon Richter. T.E. declares to have organized workshops for Esco and receiving consulting fees from Ferring and Gynemed and speakers’ fees from Esco and honorarium from Merck and MSD. T.F. received consulting fees from Vitrolife and Laboratoires Genévrier, speakers’ fees from Merck Serono, Gedeon Richter, MSD and Ferring and research grants from Gedeon Richter and MSD. M.M. received sponsorship from Merck. M.M.E. received speakers’ fees from Merck, Ferring and MSD. R.S. received a research grant from ESHRE. G.C. received speakers’ fees from IBSA and Excemed. The other authors declare that they have no conflict of interest. TRIAL REGISTRATION NUMBER N/A. DISCLAIMER This Good Practice Recommendations (GPR) document represents the views of ESHRE, which are the result of consensus between the relevant ESHRE stakeholders and are based on the scientific evidence available at the time of preparation. ESHRE’s GPRs should be used for information and educational purposes. They should not be interpreted as setting a standard of care or be deemed inclusive of all proper methods of care nor exclusive of other methods of care reasonably directed to obtaining the same results. They do not replace the need for application of clinical judgment to each individual presentation, nor variations based on locality and facility type. Furthermore, ESHRE GPRs do not constitute or imply the endorsement, or favouring of any of the included technologies by ESHRE. †ESHRE Pages content is not externally peer reviewed. The manuscript has been approved by the Executive Committee of ESHRE.


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