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Title:
RECONSTITUTION OF THE URODELE SPINAL CORD FOLLOWING UNILATERAL ABLATION - PART I. CHRONOLOGY OF NEURON REGULATION ( THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL 117, NO 3, AUG 1951 ) ( PARTIAL DOC )
Author(s):
HOLTZER, H [UNIVERSITY OF CHICAGO]
Subject Terms:
HREX
Document Location:
Location - DOE/NNSA NUCLEAR TESTING ARCHIVE Address - P.O. Box 98521 City - Las Vegas State - NV Zip - 89193-8521 Phone - (702)794-5106 Fax - (702)862-4240 Email - NTA@NV.DOE.GOV
Document Type:
JOURNAL ARTICLE
Publication Date:
1951 Aug 31
Declassification Status:
Never classified
Document Pages:
0035
Accession Number:
NV0702337
OpenNet Entry Date:
1994 Aug 27
OpenNet Modified Date:
2017 Dec 21
Description/Abstract:
THIS PAPER (THE JOURNAL OF EXPERIMENTAL ZOOLOGY) DISCUSSES THE RECONSTITUTION OF THE URODELE SPINAL CORD FOLLOWING UNILATERAL ABLATION. RESTITUTION FOLLOWING UNILATERAL EXTIRPATION OF SPINAL CORD SEGMENTS 3, 4, AND 5 WAS ACHIEVED BY MOBILIZATION OF CELLS ACROSS THE MID-LINE FROM THE INTACT HALF. ANALYSIS OF MITOTIC ACTIVITY REVEALED THAT: (1) THE INTENSITY OF MITOTIC ACTIVITY DECLINED FROM TAIL-BUD ONWARD; (2) PROLIFERATION IS PROGRESSIVELY LIMITED TO THE DORSAL PORTIONS OF THE CORD; (3) NEUROBLASTS THAT HAVE LEFT THE NEURAL EPITHELIUM MAY STILL MIGRATE AND DIVIDE. HISTOLOGICAL DETAIL IN THE RESTITUTED HALF IS A FUNCTION OF THE SOURCE OF CELLS AND THE AGE OF THE EMBRYO AT OPERATION. WHEN EARLY CELLS OF THE SHEET WERE DERIVED FROM THE ROOF PLATE OF THE INTACT SIDE, CELLS OF THE MOTOR OUTER MANTLE WERE ABSENT. CONVERSELY SUCH CELL TYPES WERE PRESENT IF THE SHEET WERE FORMED BY CELLS FROM THE INTACT FLOOR PLATE. IT IS CONCLUDED THAT THE EARLY NEURAL TUBE IS COMPOSED OF STRAINS OF NEUROBLASTS WHOSE CAPACITY FOR DIFFERENTIATION IS STRICTLY CIRCUMSCRIBED. NEUROBLASTS OF THE ALAR PLATE MAY ONLY FORM SENSORY OUTER MANTLE AND INTERNUNCIAL CELLS, WHEREAS MOTOR OUTER MANTLE CELLS ARE EXCLUSIVE PRODUCTS OF THE VENTRAL-MOST BASAL PLATE. IT IS ALSO CONCLUDED THOUGH THE MEDULLARY SYSTEM IS OF A MOSAIC NATURE, ITS SUB- SYSTEMS ARE NEVERTHELESS CAPABLE OF LIMITED DIFFERENTIAL HYPERPLASIAS. THE AUTONOMY OF THE SPINAL SUB-SYSTEMS WAS DEMONSTRATED BY THEIR CAPACITY FOR NORMAL DIFFERENTIATION INDEPENDENTLY OF THE CONDITION OF NEIGHBORING SUB-SYSTEMS.