436 SWANI VETHAMANY-GLOBUS AND R. A. LIVERSAGE
Insulin <strong>and</strong> regenerati<strong>on</strong> 437 Group B: Series V, 58- to 79-day <strong>tail</strong> regenerates. The c<strong>on</strong>trol <strong>tail</strong> regenerates showed advanced growth <strong>and</strong> differentiati<strong>on</strong> by 79 days post-amputati<strong>on</strong>, <strong>and</strong> exhibited well-defined vertebral arches (4 to 7 in number). Also spinal cord, sympathetic <strong>and</strong> spinal ganglia, skin gl<strong>and</strong>s, blood vessels, <strong>tail</strong> musculature <strong>and</strong> fins were well-differentiated at this time. In c<strong>on</strong>trast, regenerati<strong>on</strong> in the 17 experimental animals was extremely delayed, as evidenced by the small, retarded regenerates (Figs. 8, 9). Moreover, growth <str<strong>on</strong>g>of</str<strong>on</strong>g> the fins was delayed in relati<strong>on</strong> to the central axis <str<strong>on</strong>g>of</str<strong>on</strong>g> cartilage <strong>and</strong> spinal cord; this resulted in a spikelike appearance. (This type <str<strong>on</strong>g>of</str<strong>on</strong>g> regenerati<strong>on</strong> was also observed in hypophysectomized newts by Vethamany, 1970.) Mitoses were less frequently seen <strong>and</strong> some rudimentary cartilage differentiati<strong>on</strong> was evident. Tail regenerati<strong>on</strong> in the remaining eight experimental cases, however, was quite normal as indicated in Table 1 <strong>and</strong> as similar to Fig. 8. <str<strong>on</strong>g>Effects</str<strong>on</strong>g> <str<strong>on</strong>g>of</str<strong>on</strong>g>alloxan treatment Twenty animals received two injecti<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> 0-3 mg <str<strong>on</strong>g>of</str<strong>on</strong>g> alloxan per g <str<strong>on</strong>g>of</str<strong>on</strong>g> b.w. at 2-day intervals. The right <strong>forelimb</strong>s <strong>and</strong> <strong>tail</strong>s were amputated 2 days following the sec<strong>on</strong>d injecti<strong>on</strong>. However, four animals survived up to 55 days. The amputated <strong>forelimb</strong>s <strong>and</strong> <strong>tail</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> these four animals showed abortive regenerates; that is to say, they had permanent blastemata showing sparse populati<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> cells. The distal tip <str<strong>on</strong>g>of</str<strong>on</strong>g> the stump b<strong>on</strong>e was enveloped by a collar <str<strong>on</strong>g>of</str<strong>on</strong>g> cartilagenous tissue <strong>and</strong> osteoclastic erosi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> the b<strong>on</strong>e was still much in evidence at 55 days post-amputati<strong>on</strong>. Mitotic activity was minimal, extensive vacuolizati<strong>on</strong> was noticeable in the cells, <strong>and</strong> there was no trace <str<strong>on</strong>g>of</str<strong>on</strong>g> cartilage differentiati<strong>on</strong> even up to 55 days following amputati<strong>on</strong>. However, the c<strong>on</strong>trol animals (10), <strong>on</strong> the other h<strong>and</strong>, exhibited well-formed <strong>forelimb</strong> regenerates by this time <strong>and</strong> showed normal regrowth <str<strong>on</strong>g>of</str<strong>on</strong>g> the humerus, radio-ulna <strong>and</strong> four digits <strong>and</strong> had welldeveloped limb musculature (Figs. 10, 11). In the sec<strong>on</strong>d set <str<strong>on</strong>g>of</str<strong>on</strong>g> animals (20 = experimentals <strong>and</strong> 10 = c<strong>on</strong>trol) the Fig. 6. A l<strong>on</strong>gitudinal secti<strong>on</strong> through a 62-day <strong>forelimb</strong> regenerate <str<strong>on</strong>g>of</str<strong>on</strong>g> a c<strong>on</strong>trol animal. Note the well-formed cartilaginous limb skelet<strong>on</strong> <strong>and</strong> musculature. Magnificati<strong>on</strong> about x 25. Fig. 7. A similar secti<strong>on</strong> through a 62-day <strong>forelimb</strong> regenerate <str<strong>on</strong>g>of</str<strong>on</strong>g> a partially pancreatectomized adult newt showing an abnormal spike-like regenerate. Note the absence <str<strong>on</strong>g>of</str<strong>on</strong>g> radius <strong>and</strong> many digital comp<strong>on</strong>ents. Only <strong>on</strong>e digit (d) is seen. Muscles <strong>and</strong> c<strong>on</strong>nective tissue in the regenerate are c<strong>on</strong>siderably reduced as compared to the c<strong>on</strong>trol. Magnificati<strong>on</strong> about x 25. Fig. 8. A mid-sagittal secti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> a 62-day <strong>tail</strong> regenerate <str<strong>on</strong>g>of</str<strong>on</strong>g> a c<strong>on</strong>trol newt showing well-differentiated regenerate with six vertebral arches (v), spinal cord (s) differentiati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> centra in the cartilage (c) <strong>and</strong> fins (/). Magnificati<strong>on</strong> about x 40. Fig. 9. A similar secti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> a 62-day <strong>tail</strong> regenerate <str<strong>on</strong>g>of</str<strong>on</strong>g> a partially pancreatectomized adult newt exhibiting extremely small <strong>and</strong> retarded regenerate as compared to the c<strong>on</strong>trol above. Magnificati<strong>on</strong> about x 50.