2
views
0
recommends
+1 Recommend
1 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found

      Mitotic Variations in the Lens Epithelium of the Frog

      ,

      Ophthalmic Research

      S. Karger AG

      Frog, Epithelium of lens, Lens, Mitosis, Rana

      Read this article at

      ScienceOpenPublisher
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          (1) This account presents the results of a series of studies on variations in the mitotic index of frog lens epithelium.(2) Seasonal variations in mitotic index have been found in the lenses of R.catesbeiana and R.pipiens. Though the numbers of division figures vary considerably, it can be concluded that in the winter months cellular reproduction is a comparatively rare event in the epithelium of both species. By contrast, in the spring, the number of mitoses is much higher. (3) It is suggested that temperature may be an important factor in regulating the MI; possibly more important than endogenous factors implicated by many workers for other types of circadian and circannual variation (4) Animals maintained at 24 °C during the coldest part of the year manifest a normal range of proliferative activity while in frogs maintained in the cold during the warmer periods mitosis is abolished. (5) Additionally, animals which have arrived at the laboratory after having been exposed to cold temperature (in transit), have mitotic indices which are increased as some function of the number of days acclimation to room temperature. (6) What is more, during the calendar time of hibernation, the proliferative response elicited by injury or in vitro culture seems to be enhanced if the animals from which the lenses are obtained are acclimated for long periods. (7) No diurnal variation was discerned in the lenses of these animals. This finding disagrees with the results from similar studies on mammalian lenses. (8) In agreement with studies on mammalian lenticular material was our finding that there is some relationship between age and MI. However, this becomes obvious only when one compares very young (i.e. 2.5–11 months post-metamorphosis) to adult organisms (24 + months post-metamorphosis). (9) These results were evaluated and discussed in relation to previous work from our laboratory as well as to relevant studies from other groups. A number of seemingly appropriate follow-up investigations were recommended.

          Related collections

          Author and article information

          Journal
          ORE
          Ophthalmic Res
          10.1159/issn.0030-3747
          Ophthalmic Research
          S. Karger AG
          0030-3747
          1423-0259
          1972
          1972
          09 December 2009
          : 3
          : 2
          : 95-107
          Affiliations
          Department of Zoology, University of Vermont, Burlington, Vt.
          Article
          266174 Ophthal Res 1972;3:95–107
          10.1159/000266174
          © 1972 S. Karger AG, Basel

          Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher. Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug. Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.

          Page count
          Pages: 13
          Categories
          Paper

          Vision sciences, Ophthalmology & Optometry, Pathology

          Frog, Epithelium of lens, Lens, Mitosis, Rana

          Comments

          Comment on this article