摘要:

AbstractAutoradiography following labeling with H‐3‐thymidine was used to study the pattern of growth of injury‐induced lentomas inRana pipiens. This reaction to injury was compared with the more controlled reaction in the rabbit lens, which has been extensively studied by others.These studies show that, unlike that of the rabbit, the entire lens epithelium of the frog reacts within a day to the injury stimulus by disarrangement of its normal architecture. H‐3‐thymidine is incorporated between 24 and 40 hours post‐injury, followed subsequently by widespread mitotic activity. Peak thymidine incorporation occurs at three days and peak mitosis at five days post‐injury. However, the stimulus to mitotic activity is propagated after the first week largely among the superficial cells of the enlarging lentoma and adjacent normal epithelium; DNA synthesis and mitosis in the deeper cells of the lentoma diminish at a week and cease by two weeks post‐injury, and by three weeks in the superficial cells.It is concluded that the frog lentoma is formed by accretion from the surface as a result of extensive multiplication of cells throughout the injured epithelium. The reaction of frog and rabbit lenses to injury differs both in the extensiveness of the initial reaction and the duration of the stimulus t

ISSN:0003-276X    

DOI:10.1002/ar.1091530202

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

年代:1965

数据来源: WILEY

摘要:

AbstractA simple method is described for the preparation of cleared and injected “whole‐mounts” of large masses of tissue (for example the mediastinal contents). This technique allows the use of high magnifications during examination and microphotography and the use of histological controls. It provides a novel method for detailed topographical studies because each tissue has its own distinctive vascular pattern which delineates it clearly.A direct three‐dimensional inspection has many advantages over the usual methods of dissection, or reconstruction from serial sections. This is particularly true of microcirculations, fine autonomic nerve patterns and the distribution of aberrant tissues (thyroid, parathyroid, etc.). Other distinctive features of tissues, such as positive chromaffin staining or the uptake of injected substance by the reticulo‐endothelial system, can also be demonstrated.The results obtained are demonstrated by photographs of “whole‐mounts” from dogs and adult and fetal cats. The advantages and disadvantages of the metho

ISSN:0003-276X    

DOI:10.1002/ar.1091530203

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

年代:1965

数据来源: WILEY

摘要:

AbstractExperiments were conducted on the incisor of young rats to show (1) the precise areas and manner in which the tetracycline fluorophore combines with dentin and enamel and (2) the relation between the tetracycline localization and mineralization. For the objectives mentioned above rats were injected with tetracycline and a combination of tetracycline and Ca45. Detailed examination of the teeth of specimens injected with tetracycline show a rapid uptake and localization of fluorophore in areas undergoing mineralization. Areas adjacent to the increments undergoing mineralization also reveal the presence of the fluorophore, but to a lesser extent. Comparison of the same area of the tooth injected with tetracycline and Ca45show that the fluorophore is localized exclusively in areas undergoing mineralization, and to a lesser extent in adjacent, incompletely mineralized regions.Despite the fact that our observations have demonstrated the avidity tetracycline exhibits for mineralizing and recently mineralized areas of dentin and enamel, we have not been able to exclude the possibility that the fluorophore may combine with the organic matrix of these tissues as well as the mineral component.

ISSN:0003-276X    

DOI:10.1002/ar.1091530204

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

年代:1965

数据来源: WILEY

摘要:

AbstractThe lymphatic system of the sloth (Bradypus tridactylus) was described after the study of five specimens captured in Brazil. The lymphatic system was injected with Prussian blue suspension and neoprene latex (the latter followed by partial corrosion). The description includes lymph nodes, lymphatic networks, vessels and trunks. The distribution of these structures follows the general pattern of otherXenarthra, namely,Dasypus, EuphractusandTamandua. However, the following peculiarities were noted: the submandibular, popliteal and posterior mediastinal ll.nn., the abdominothoracic subcutaneous lymphatic collecting vessels, the true principal lymphatic trunks, the cisterna chyli, and the thoracic duct were missing inBradypus tridactylus.The mesenteric ll.nn. do not fuse and their efferent vessels intermingle with those originating from the cecocolic ll.nn. forming a mesenteric lymphatic plexus. The lymphatic vessels arising from the submucous network of the descending and sigmoid colon are arranged as parallel lamellae similar to those inDasypus.The efferent collecting vessels from several abdominal organs ultimately empty directly in the inferior vena cava and its trunks of origin and those coming from the bronchial ll.nn. lead to the azygos vein. This feature reminds one of the conditions described in some monkeys. The mesenteric postlymphonodal plexus is well developed and because of the absence of intercalated lymph nodes in the labrinthine circulation it resembles that of amphibia and birds.

ISSN:0003-276X    

DOI:10.1002/ar.1091530205

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

年代:1965

数据来源: WILEY

摘要:

AbstractTypical immature pubic joints developed when undifferentiated mesenchyme from the pelvic region of 13‐day‐old embryos was grownin vitroon a Millipore filter. After five days the joints were transplanted to 5‐day‐old postnatal female mice whose pubic joints were excised prior to transplantation. The transplanted joints developed to adult‐type symphyses and replaced the excised joints of the recipients. Typical bone resorption and cartilage transformation to ligamentous tissue occurred in transplanted joints in pregnant r

ISSN:0003-276X    

DOI:10.1002/ar.1091530206

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

年代:1965

数据来源: WILEY

摘要:

AbstractAn electron microscopic investigation was made on lysosomes and morphologically related structures found in cardiac muscle. The tissues used in this investigation were obtained from normal and functionally altered rat hearts and human hearts from patients with cardiomyopathy.Structures morphologically similar to lysosomes were encountered in all hearts, but were especially numerous in the damaged hearts, both human and rat. These structures were extremely variable in size, the smaller ones being located in the Golgi region where they appeared to originate.Lipofuscin granules were especially numerous in pathological hearts, and have several morphological features in common with lysosomes.Other bodies were also frequently encountered in these cells which in many ways resembled lysosomes, but contained mitochondria, fragments of mitochondria and myelin figures.The structural similarities between lysosomes and these other elements lead us to consider the possibility that the latter structures may be modified, degenerate, or simply functional stages of lysosomes.

ISSN:0003-276X    

DOI:10.1002/ar.1091530207

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

年代:1965

数据来源: WILEY

摘要:

AbstractThe differentiation of the fibroblast was followed in the dental pulp of continuously growing incisors of the guinea pig. Based on the ultrastructure, the processes of differentiation of the fibroblasts might be conveniently broken into three stages; Stage I – period of early differentiation, Stage II – period of maturation and functioning, and Stage III – period of regression.During Stage I the cell had structural characteristics shared by other less differentiated cells. The endoplasmic reticulum was poorly developed, showing vesicular to tubular profiles. The ribosomes were abundant but were mostly distributed in free form. Mitochondria were small and had irregular interiors.Stage II was characterized by a striking development of the rough‐surfaced endoplasmic reticulum, which appeared in various shapes and sizes. The Golgi complex was enlarged, and contained some fibriller materials in dilated portions of its membraneous elements. Other features described in the cytoplasm of fibroblasts from other sources were confirmed.Stage III was characterized by the decrease in size and number of various cytoplasmic constituents and was considered to represent cells in the state of reg

ISSN:0003-276X    

DOI:10.1002/ar.1091530208

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

年代:1965

数据来源: WILEY

摘要:

AbstractEggs of sheep were recovered at known intervals before or after controlled ovulation. They were examined for cytoplasmic and nuclear changes. The vesicular nucleus in the follicular egg persists to 15 hours before ovulation when the chromatin becomes more compact and dense. The first metaphase lasts from 13 hours before ovulation to shortly before ovulation. The formation of the first polar body occurs from four hours before ovulation to ovulation. Normally sheep eggs have formed the first polar body by the time of ovulation and are in the seocond metaphase. Cumulus cells and corona cells are present on the egg at ovulation and for a few hours afterwards. Sperm penetration does not begin ordinarily until at least three hours after ovulation. The male pronucleus forms from 3 to 9 hours after ovulation at about the same time as the female pronucleus. Pronuclei fusion occurs 11 to 22 hours after ovulation. The first mitotic division takes place usually 19 to 24 hours after ovulation although 2‐called eggs were seen at earlier time

ISSN:0003-276X    

DOI:10.1002/ar.1091530209

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

年代:1965

数据来源: WILEY

ISSN:0003-276X    

DOI:10.1002/ar.1091530201

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

年代:1965

数据来源: WILEY