摘要:

AbstractThe fine structure of cerebral cortical synapses was investigated during failure of synaptic transmission produced by ischemia. Presynaptic and postsynaptic potentials evoked in the anterior sigmoid gyrus of the cat by stimulation of the nucleus ventralis lateralis and the DC potential between cortical layer IV and the white matter were recorded with micropipettes during cerebral ischemia produced by arterial hemorrhage in paralyzed, artificially ventilated animals. After failure of the spontaneous electrocorticogram and postsynaptic responses, the presynaptic volley failed with development of depolarization of intracortical fiber terminals and loss of axon terminal excitability. The gyrus was then biopsied and fixed in collidine‐buffered OsO4. An altered pattern of distribution of synaptic vesicles was observed after presynaptic afferent fiber terminal activity was abolished by 3.5 to 4.0 minutes of cerebral ischemia. Clumping of vesicles in a region away from the cynaptic cleft was seen in about 10% of synaptic endings, and there was more than a two‐fold increase in the number of presynaptic profiles devoid of vesicles in ischemic cor

ISSN:0003-276X    

DOI:10.1002/ar.1091660202

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

年代:1970

数据来源: WILEY

摘要:

AbstractImplanted fragments of liver in ectopic sites do not survive. The failure of survival is associated with lack of vascularization. This results in necrosis of coagulative type which later is replaced by connective tissue. An invasion of polymorphonuclear leukocytes can enhance the rate of this process. Regenerative stimuli such as partial hepatectomy do not change this sequence of events. The lack of vascularization of implants may be due to failure of eliciting an invasive vascular phenomenon which is seen in the implanted fragments of those tissues that survive in ectopic sites.

ISSN:0003-276X    

DOI:10.1002/ar.1091660203

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

年代:1970

数据来源: WILEY

摘要:

AbstractNecropsy examinations were performed on 100 dogs to study the biliary system, blood supply, and topographic anatomy of the liver. The major ligamentous attachments of the relatively mobile organ are the left triangular and hepatoduodenal ligaments. Considerable fixation is provided by the hepatic veins and the intimate attachment of the liver to the inferior vena cava.The six lobes of the liver are arranged in three natural divisions. The portal vein, its branches, and their distribution are consistent as are major hepatic veins. The hepatic artery branches and major bile ducts have patterns which may be readily related to the divisional boundaries. The branches of the hepatic artery vary in number from one to five. Three branches were present in 64 of 100 specimens. A single gallbladder and cystic duct were found in each of 100 specimens. The common bile duct is formed from three (64%) or four (36%) major collecting or divisional ducts. When four divisional ducts are present, the right and left divisions of the liver are each drained by a single duct with two ducts draining the central division. The cystic duct may join either the right or left central divisional duct to form the common bile duct.

ISSN:0003-276X    

DOI:10.1002/ar.1091660204

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

年代:1970

数据来源: WILEY

摘要:

AbstractThe distribution of glycogen in chick hearts was studied during incubation and one week following hatching. Concurrent histochemical and chemical studies revealed a gradual increase in the deposition of glycogen during the first half of incubation. During the latter half of incubation the average content of chemically extractable glycogen remained relatively stable until day 19 when a significant decline (p<0.001) was noted. This decrease was attributed chiefly to the decline in the acid‐soluble fraction.Throughout the incubation period significantly greater (p = 0.05) amounts of chemically extractable glycogen were present in the left chambers and interventricular septum than in the right chambers. These differences were not evident in the post‐hatched chick.Histochemically, glycogen was demonstrated in the chick hearts throughout the incubation period, but no appreciable amount was detected in the hearts one week after hatching. Chemical analysis of the latter revealed that the glycogen content was below the threshold thought to be necessary for its histochemical demonstration.Parallel decreases noted in both the depth of stain intensity and the acid‐soluble fraction serve as further evidence that the acid‐soluble fraction is primarily responsible for the histochemical reaction observed with glycogen

ISSN:0003-276X    

DOI:10.1002/ar.1091660205

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

年代:1970

数据来源: WILEY

摘要:

AbstractThe role played by the ectodermal component during lower vertebrate tooth development has been a subject of much speculation. In order to provide new information on this matter the cytostructural changes occuring in the ectodermal part of the tooth buds of a small fresh water fishHelostoma temminckiwere investigated.The cells of the two epithelial layers which form the ectodermal cap of the tooth bud showed little sign of specialization during the early phase of tooth formation. There was no evidence of the synthesis and secretion of enamel matrix. With the onset of the calcification of the dentin specializations indicating an absorptive activity were observed in the cells of the outer epithelial layer. These changes consisted of an elaborate system of canalicular spaces and coated vesicles. Concurrently the cells of the inner layer accumulated large amounts of iron in the form of ferritin particles. The iron was subsequently deposited over the outer layer of the dentin imparting a reddish‐brown coloration to the teeth.The ultrastructural specialization of the ectodermal component during tooth development are suggestive of transport functions similar to those which are thought to occur in post‐secretory enamel organs during the maturation of ena

ISSN:0003-276X    

DOI:10.1002/ar.1091660206

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

年代:1970

数据来源: WILEY

摘要:

AbstractPara‐anal organs of nine specimens of the rare, Southeast Asian bat Eonycteris spelaea were studied in serial sections by light microscopy. Parenchymal tissue of the organs consists of solid cords of cells budded from the naked epidermis without association with hair follicles. Cytological characteristics and cytomorphosis of para‐anal gland cells differ markedly from those of typical sebaceous glands in adjacent haired skin, and the phases of growth, differentiation and secretion appear to be segregated in time. Nevertheless, holocrine secretory activity and a sebum‐like secretion occur in this highly specialized sebaceous organ. Although found in both sexes, it is larger in adults, in males as compared with females, and in reproductively more active males as compared with males of the same size but with smaller t

ISSN:0003-276X    

DOI:10.1002/ar.1091660207

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

年代:1970

数据来源: WILEY

摘要:

AbstractSpecialized intercellular junctions have been observed in 3‐methylcholanthrene‐induced mouse sarcomas. These junctions are of two morphologic types and appear to be focal in nature. The first type consists of an approximation of the plasma membranes of adjacent cells to within 200 Å of one another. In the junctional region the intercellular space and the adjacent cytoplasm are of increased density. The second type of junction is more complex, the intercellular space being of greater width and containing a dense central plaque. The intercellular space and the adjacent cytoplasm are of increased density. Such junctions may serve a role in structural support of the tumor

ISSN:0003-276X    

DOI:10.1002/ar.1091660208

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

年代:1970

数据来源: WILEY

摘要:

AbstractThe relation of the autonomic nerve supply of the pelvis to the visceral pelvic fascia and in particular that of the parasympathetic supply to the bladder musculature is of particular consequence in pelvic operations. It is observed that the pelvic splanchnics, including those branches supplying the bladder, are embedded in the peripheral component of the visceral pelvic fascia or presacral fascia throughout a considerable part of their course. Early anatomists made no distinction between the presacral fascia and the fascial sheath of the rectum proper. Consequently their illustrations shown only a single fascial layer which they call the “rectal fascia” or “posterior fibrous sheath of the rectum” separating the middle sacral vessels from the superior rectal vessels which lie in the pararectal fat. While such a distinction has since been made in the surgical literature, most anatomical descriptions are still rather vague in this respect. It is essential to develop the plane of cleavage between the presacral fascia and the fascial sheath of the rectum if injury to the pelvic splanchnic nerves is to be

ISSN:0003-276X    

DOI:10.1002/ar.1091660209

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

年代:1970

数据来源: WILEY

摘要:

AbstractThe differentiating sebaceous cells in three species of galagos have different structural configurations of cytoplasmic membranes. The type unique to G.senegalensisconsists of groups of six tubules, which intersect at common centers. The tubules of this configuration probably represent a specialized form of agranular endoplasmic reticulum. A second specialized form of agranular endoplasmic reticulum is found in all three species of galagos; this configuration consists of grids of intersecting tubules that are ∼400 Å in diameter. Individual tubules of agranular endoplasmic reticulum are also abundant in the cells.Another disposition of cytopalsmic membranes, found only inG. crassicaudatus, is significantly different from the others. In this structure, membranes intersect in three planes to form hexagrams. All of these configurations are closely associated with single, dispersed profiles of predominantly agranular endoplasmic reticulum and sebum vesicl

ISSN:0003-276X    

DOI:10.1002/ar.1091660210

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

年代:1970

数据来源: WILEY

摘要:

AbstractEruption was studied by experimentally impacting and releasing permanent premolars in puppies. Eruption rates of both normal and experimentally delayed teeth were calculated from weekly radiographs. The rate of normal eruption is triphasic and similar to a normal growth curve. It has an initial slow exponential rate which changes to a more rapid exponential rate followed in turn by a terminal plateau. All of the teeth released from impaction erupted and their rates exceeded or equaled the normal rate.The morphology of the bony trabeculae beneath the erupting teeth and the relative amount of soft tissue between the bone and teeth are expressions of the eruptive rate. The trabeculae around rapidly erupting teeth are thinner, more delicate and more widely separated from one another than those of slowly erupting teeth. Trabecular orientation aligns with the direction of eruption, showing not only its vertical component, but also whether the tooth moved mesially or distally during eruption.

ISSN:0003-276X    

DOI:10.1002/ar.1091660211

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

年代:1970

数据来源: WILEY