摘要:

AbstractThe area of new cell formation, the rate of proliferation, and the manner in which cells are lost from the intestinal epithelium in the turtle,Chrysemys picta, were studied using a cell labeling technique with tritiated thymidine and mitotic inhibiting technique with colchicine.In the intestinal epithelium ofChrysemys picta, cellular proliferation was observed to occur in the layer of cells adjacent to the basement membrane. Mitosis occurred throughout the epithelium at a fairly low rate (mitotic index 0.0016). In the upper intestine fewer labeled cells were found in the apical one‐third of a villusfold than in either the mid or basal one‐third. The time required to renew the intestinal epithelium, was estimated to be about eight weeks in winter turtles maintained at 20° to 24°C.Cell loss from the system appeared to be due to a randomly located movement of cells lumenward from the basement membrane.Mitotic activity in cold torpid turtles (11°C ambient temperature) appeared to be completely suppressed as shown by a lack of incorporation of tritiated thymidine and an absence of mitotic figures in the intestinal epithelium.The term villi‐folds was proposed to provide a category for those animals possessing structures having characteristics both of villi and of folds as found in

ISSN:0003-276X    

DOI:10.1002/ar.1091480302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1964

数据来源: WILEY

摘要:

AbstractExperiments reveal that growth reactions may be evoked in amputated forelimbs of fully adultRana pipiensandR. catesbianaby electrical stimulation of the normal limb nerve supply. The evoked growths were generally small cones, 5–10 mm in length; none developed into limbs of normal size and morphology, but some formed digits and cartilage and developed striated muscle. The combined influences of trauma, effected by salt treatment, and electrical stimulation of the nerve produced more growths than trauma or stimulation alon

ISSN:0003-276X    

DOI:10.1002/ar.1091480303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1964

数据来源: WILEY

摘要:

AbstractConventional radiographs of lungs of calves which had been injected post mortem with barium sulphate could not be used to demonstrate vessels smaller than 50 μ in diameter. To overcome this difficulty, frozen sections 50–150 μ thick were floated on to high resolution photographic plates and contact microradiographs made using soft radiation. The resultant microradiogram was then viewed and photographed with the light microscope. It was possible to visualize the smaller arterioles and the capillary networks around the alveoli. The technique is simple and gives reproducible resu

ISSN:0003-276X    

DOI:10.1002/ar.1091480304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1964

数据来源: WILEY

摘要:

AbstractFifty day old Sprague‐Dawley rats were given sodium fluoride (50 mg/kg) and killed at times between one half hour and 32 days after injection. Transverse sections of the upper incisor 40 μ thick were radiographed, demineralized and stained with hematoxylin and eosin. The response seen in hematoxylin and eosin stained material agreed with previous descriptions of the “calciotraumatic response” and consisted of three components. However, in the radiogram only two components could be distinguished: an external hypermineralized zone and an adjacent hypomineralized zone. The radiographic response was first recognized four hours after injection as a narrow zone of hypermineralized dentin at the dentin‐predentin junction. When the radiograms were compared to the H and E stained sections in animals killed up to 19 hours after injection, two important features were observed: (1) the width of the predentin had increased markedly, and (2) the hypermineralized zone had increased to its final width. This was interpreted as concurrent formation of both hypermineralized and hypomineralized components. At 24 hours normal dentin formation had resumed. Since both components were forming simultaneously it is believed that sodium fluoride does not cause the response by interfering with the humoral mechanisms of mineralization, but, rather, its effect is most likely on collagen or ground s

ISSN:0003-276X    

DOI:10.1002/ar.1091480305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1964

数据来源: WILEY

摘要:

AbstractThe secretion of protein by the acinar cells of the pancreas occurs in two steps: the synthesis of the protein from amino acids and its migration through the cell to the acinar lumen. Since very soon (one minute) after the injection of leucine‐H3the labeled protein is found mainly in the ergastoplasm of the basal half of the cell, protein synthesis is believed to occur in this location. At later intervals the labeled protein is found in the Golgi complex (10 and 30 minutes), and then in the zymogen granules of the apical half of the cell (60 minutes). The newly synthesized protein thus migrates from the ergastoplasm to the Golgi complex, and from there as zymogen granules through the apical half of the cell prior to being released in the acinar lume

ISSN:0003-276X    

DOI:10.1002/ar.1091480306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1964

数据来源: WILEY

摘要:

AbstractThe volumes of parenchymal cells and their nuclei in liver were calculated in white rats, Columba livia (rock pigeon), Calotes versicolor (garden lizard) and Bufo melanostictus (toad); from their optical area and cell thickness. The area was measured from camera lucida drawings. The largest cellular and nuclear volume was observed in rats and smallest in pigeons. The cell volume in toads was similar to that found in rats but they had smaller nuclei. The cellular and nuclear volumes in lizards were smaller than in toads; and in pigeons smaller than lizards. The significant difference, in both cellular and nuclear volumes that has been observed in different classes of vertebrate, cannot be correlated with the evolutionary changes.

ISSN:0003-276X    

DOI:10.1002/ar.1091480307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1964

数据来源: WILEY

摘要:

AbstractUDPG‐glycogen synthetase was studied in the uterus of ovariectomized and ovariectomized‐hormone treated rabbits and in the tongue. Following the biochemical technic of Leloir and Goldenberg it was not possible to demonstrate the enzyme in the uterus of the ovariectomized or ovariectomized treated animals. However, in the tongue the enzyme was present. The data from this study along with previous histochemical studies indicates that the glycogen in the uterine muscle is not synthesized through the UPDG pathway, but is synthesized from G‐1‐P by the action of phosphorylase. Since UDPG‐glycogen synthetase can be demonstrated in the tongue a difference seems to exist in glycogen synthesis between the smooth muscle of the uterus and skeletal muscle of t

ISSN:0003-276X    

DOI:10.1002/ar.1091480308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1964

数据来源: WILEY

摘要:

AbstractIn this study the distribution of mast cells in the cephalic, middle, or caudal portions of the uterine horns did not differ. In cross‐sections, however, mast cells were most numerous in the myometrium, intermediate in the tunica vasculare of the endometrium and least in the mucosa. In the endometrium, the mast cells were most numerous in the antimesometrial, least in the mesometrial and intermediate in the lateral quadrants. In the myometrium, however, the relative numbers of mast cells between the quadrants varied according to the day in the estrous cycle.On days 1 (the day after estrus), 2, 3, and 4, (the day of proestrus) of the estrous cycle, there were respectively 42.7, 21.8, 22.5 and 10.7 mast cells in the endometrium per 12 μ sections. The differences in means between groups was highly significant (P<0.001). In mated females on 67, 79, 91, 103, 115, and 151 hours after ovulation, there were respectively 9.4, 8.4, 4.7, 5.6, 2.1, and 2.2 mast cells in the endometrium per 12 μ cross‐section. The differences in the means were not significant.The mean number of mast cells per 12 μ cross‐sections of uteri of ovariectomized females was 20 ± 8. Subcutaneous injections of 0.3 gamma estrogen did not significantly alter the number of mast cells but 0.6 gamma depressed the mean count to 11 ± 7.It appeared from these studies that the uterine mast cell numbers were related to the cyclic phenomena of estrous, but that the numerical relationship to the time of nidation was

ISSN:0003-276X    

DOI:10.1002/ar.1091480309

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1964

数据来源: WILEY

摘要:

AbstractColloidal mercuric sulfide injected into the rete testis adhered to the stereocilia of the epithelial cells and subsequently moved into a highly developed canalicular system in the apical cytoplasm. The canalicular invaginations of the cell surface arising between the stereocilia lead to cytoplasmic vacuoles that concentrate the particulate matter. The limiting membrane of the stereocilia and of the canaliculi and vacuoles is covered by a layer of amorphous material. It is speculated that this may bind particles, molecules, and ions as does an ion exchange resin, and that it may, in this way, act as a carrier in the uptake and transport of substances by cells.

ISSN:0003-276X    

DOI:10.1002/ar.1091480310

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1964

数据来源: WILEY

ISSN:0003-276X    

DOI:10.1002/ar.1091480301

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1964

数据来源: WILEY