Book - Contributions to Embryology Carnegie Institution No.35

From Embryology

Muscular Contraction In Tissue-Cultures

By Margaret Reed Lewis,

Collaborator in the Department of Embryology, Carnegie Institution of Washington.


With two plates and six text figures.



Links: Carnegie Institution of Washington - Contributions to Embryology


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Introduction

The solution of the problem of the structure and behavior of muscular tissue has been frequently undertaken either from the standpoint of detailed and complicated cell architecture or from that of the mechanics of dead material. It is by no means claimed that the observations herein recorded solve this most interesting problem; nevertheless the results show that it is possible to consider the question entirely from the standpoint of hving material and at the same time to be able to disregard to a great extent the comphcated structure of differentiated muscular tissue. In other words the mechanism to be observed can be reduced to the simple terms of a single sUghtly differentiated, U\dng cell maintained under observation throughout experimentation.

METHOD

Although a new procedure, the tissue-culture method is well known, in view of the fact that when it was first used conclusive results were obtained in two of the important problems of anatomy and physiology— t. e., that the axons grow out from the nerve cells (Harrison, 1910) and that the heart muscle is capable of independent contraction (Burrows, 1912). The method used in the present experi- ments, while similar in most respects to that of Dr. Harrison and also that of Dr. Burrows, was devised for the study of the cells of the blood, bone marrow, and spleen, in relation to tuberculosis, independent of the work of the above authors. The original solution contained agar. Since it was found (Lewis and Lewis, 1912) that the presence of agar is not necessar}' for growth of the cells, the Locke-Lewis solution, modified (M. R. Lewis, 1916) according to the species of animal and also according to the osmotic pressure of the tissue to be explanted, has been employed.


Tissues from chick embryos of 4 to 12 days' incubation were used for the cultures. The medium was Locke-Lewis solution (90 c.c. of NaCl 0.9 per cent + KCl 0.042 per cent + CaCL, 0.025 per cent + NaHCOj 0.02 per cent -|- 10 c.c. of chicken bouillon -f 0.25 per cent dextrose; Lewis and Lewis, 1915). Aseptic conditions were maintained throughout. The embryo was removed from the egg and placed in a petri dish containing 20 c.c. of warm solution. Pieces of the tissues to be explanted were removed, washed through one or more changes of warm medium, and cut up with sharp scissors into pieces about 0.5 mm. in diameter. Each piece was then placed on the center of a cover sUp, part of the drop drawn off, and the cover slip sealed on to a vaseUne ring around the well of a hollow-ground slide. Cultures thus prepared were kept in an incubator at 39° C. All microscopical observations and experiments were made in a warm box at 39° C.


The cells began to migrate out from the explanted piece within a few hours. At the end of 18 hours a zone of cells, usually only a few cells deep but often wider than the cx[)hinted piece, was formed. Among the cells of this new growth were man,v mitotic figures (figs. 7, 8, and 9). As the cells migrated out they became spread out more and more closely ujjon the under surface of the cover slip, so that the edge of the growth was composed of a single layer of large, flat cells. These flat cells, although somewhat distorted in so far as the position of certain cytoplasmic structures are concerned, have an advantage over those obtained bj' means of sections, in that all the structures of the cell are present and can be observed in their relations throughout the activity of the Uving cell. The region between these outer cells and the explanted piece may be one or several cells in depth. The cells here, while largely spread out, resemble more nearly the cells of the normal embryo and are very httle distorted laterally.


8i)ontaneously contracting cells usually were found among the less spread- out cells and not among those at the edge of the growth. Cultures of the amnion furnished numerous rhythmically contracting smooth-muscle cells ; those of the heart gave rise frequently to sheets of cells contracting in co-ordination with the beat of the explanted jiiece, and at times to a few isolated cells beating independently; while from the skeletal muscle were obtained muscle buds, muscle-fibers, and myoblasts, each of which were occasionally found undergoing spontaneous contraction.


For a better understanding of the cells in tissue-culture various preparations of other living muscular tissues were made, among which may be mentioned the following: (1) The entire uninjured amnion of a 3, 4 or 5 day chick embryo; (2) a 2 to 3 day chick embryo with beating heart ; (3) preparations of teased heart muscle and teased skeletal muscle-fibers of chick embryos; (4) certain microscopical marine copepods whose cross-striated muscle-fibers could be studied while the animal remained alive; (5) the isolated sarcostyles of the insect's wing muscle; (6) thin slices of the muscle-fibers from an adult dog, cat, or turtle. In addition to the above, preparations were fixed and stained in various ways in order to compare the results with those of other investigators.



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Historic Disclaimer - information about historic embryology pages 
Mark Hill.jpg
Pages where the terms "Historic Textbook" and "Historic Embryology" appear on this site, and sections within pages where this disclaimer appears, indicate that the content and scientific understanding are specific to the time of publication. This means that while some scientific descriptions are still accurate, the terminology and interpretation of the developmental mechanisms reflect the understanding at the time of original publication and those of the preceding periods, these terms and interpretations may not reflect our current scientific understanding.     (More? Embryology History | Historic Embryology Papers)


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Cite this page: Hill, M.A. (2019, October 21) Embryology Book - Contributions to Embryology Carnegie Institution No.35. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Book_-_Contributions_to_Embryology_Carnegie_Institution_No.35

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