摘要:

AbstractThe objective of this study was to define further the role of the trigeminal motor nucleus (TMNu) in the postnatal ontogeny of the mammalian craniofacial skeleton. To that end, 42 male Sprague‐Dawley rats underwent stereotaxic surgery at 40 days of age; 21 received small electrolytic lesions to their left‐side TMNu (lesioned group) while 21 had TMNu stimulation with no actual electrolytic lesion produced (sham group). Seven rats from each group were killed at 28, 56, and 84 days postoperative to analyze trigeminal motoneuron (TMNe) count, masticatory muscle weight, and osteological growth vector data. At all three time periods, lesioned animals showed significant differences (1) between the surgery and nonsurgery sides, and (2) from sham animals. However, sham animals also demonstrated significant between‐side differences for medial pterygoid muscle weight (56 days), mandibular height (28 and 56 days), and mandibular length data (84 days); these data suggested that even relatively slight damage to TMNe can create morphological changes within the craniofacial complex. Snout deviation in a lesioned rat towards the opposite side from all other lesioned animals was correlated with unique damage to its pontine reticular formation; this suggested that the observed morphological alterations of the craniofacial complex may have been due not only to TMNu damage, but also to changed expressions of the masticatory central pattern generator (CPG). Morphological alterations of the craniofacial skeleton resulting from lesions to the TMNu were likely due to changed neuromuscular activity patterns of the masticatory muscles and their biomechanical effects upon

ISSN:0002-9106    

DOI:10.1002/aja.1001890202

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

年代:1990

数据来源: WILEY

摘要:

AbstractMany aspects of the blood vascular network of the lymph node are unknown, and others need confirmation. We have studied the blood vasculature of rat peripheral lymph nodes by means of carbon perfusion and vascular cast corrosion techniques. At the hilus of the node, an artery gives off arterioles running in medullary cords towards the cortex. Some reach the peripheral cortex directly, branching there into slender cortical vessels. Other arterioles enter the periphery of the deep cortex units, and then head towards the peripheral cortex. Upon reaching it, they curve part way above the center of the deep cortex units and provide slender branches to the overlying peripheral cortex. Dense plexuses of capillaries arise from arterioles in the medullary cords, in the periphery of the deep cortex units, and in the outermost stratum of the extrafollicular zone of the peripheral cortex. In the cortex, the draining high endothelial venules are restricted to the extrafollicular zone and to the periphery of the deep cortex units. At the cortico‐medullary junction, these peculiar venules transform into regular medullary venules which form the hilar veins. In contrast, the folliculo‐nodules and center of the deep cortex units are little vascularized by a loose capillary network, while no vessels occur in the subsinus layer. These features of the node vascular network are of interest in relation to the node architect

ISSN:0002-9106    

DOI:10.1002/aja.1001890203

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe human rhombencephalon at 8 postovulatory weeks (stage 23) is described and illustrated for the first time with the aid of silver‐impregnated sections and graphic reconstructions. The motor and sensory trigeminal nuclei were among those studied, and the latter was found to be almost contiguous to the dentate nucleus. Fibers to the principal sensory nucleus join the mesencephalic trigeminal tract, which also seems to be connected with the motor fibers. Fine fibers from the sensory root join the tractus solitarius, which appears to receive connections from the facial, glossopharyngeal, and vagal nerves. Main and accessory abducent nuclei are evident. A part (theKappenkern des Facialisknies) of the nucleus funiculi teretis is particularly prominent. The presence of the pyramidal decussation during the embryonic period is noted for the first time. The arrangement of nuclei and tracts at 8 weeks is shown to be closely similar to that present in the newborn, and it is likely that the rapid growth of the rhombencephalon during the embryonic period proper is associated with correspondingly early functional activit

ISSN:0002-9106    

DOI:10.1002/aja.1001890204

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe innervation of human teeth and oral mucosa has been studied in the past by different methods, none of which offered a clear description of the precise morphology of nerve fibers and terminals and of nerve organization as a whole. Recently, interesting findings have been obtained by means of immunohistochemical investigations for neurofilaments and S‐100 proteins. A new brain‐specific molecule, protein gene product 9.5 (PGP 9.5), has been used for the first time in the present research to investigate the distribution of nerves in human oral mucosa and decalcified teeth, about which there is a paucity of information. The data provided in this study, confirming previous work in other species, may be of value for understanding the anatomy of human oral innervation. In the oral mucosa, the antiserum labels nerve fibers, corpuscles, and neuroendocrine (Merkel) cells. In sections of decalcified teeth, numerous PGP 9.5 positive fibers are demonstrated in the pulp and in the inner 100 μm of dentin. The novel nerve tissue protein used, PGP 9.5, thus appears to be a reliable marker for studies of nerve fibers in human tissues and not to be affected by decalcification procedures. It could then be used for investigations on the innervation of normal and pathological calcified human tis

ISSN:0002-9106    

DOI:10.1002/aja.1001890205

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe epithelium of the human tongue shows diverse morphological variations from one site to another and even within the epithelium of the same papilla. This complexity has led to confusion regarding tongue epithelium as being orthokeratinized, parakeratinized, or nonkeratinized.Cytokeratins have been shown to characterize different epithelia. The present paper describes cytokeratin expression by adult tongue epithelia and relates their distribution to morphology. Six healthy human tongue specimens were obtained after plastic surgery and cytokeratin expression was investigated immunohistochemically, using a panel of 15 antibodies for cytoskeletal proteins, and biochemically using two‐dimensional gel electrophoresis.The results showed that the ventral and lateral surfaces of the tongue are related to the nonkeratinizing stratified squamous epithelia, esophageal type, whereas the dorsal surface showed mixed expression of cytokeratins. In the tip of filiform and on the surface of fungiform papillae, cytokeratins of terminal differentiation are expressed as skin type; and in the rest of the papillae as well as in interpapillary areas, the epithelium expresses esophageal type cytokeratins. Certain simple epithelial cytokeratins were found in taste buds. Cytokeratin 19 was also detected in the basal cell layer of all esophageal type epithelia in the tongue.The present results provide basis for studies on the biological events in epithelial differentiation during development and in patholog

ISSN:0002-9106    

DOI:10.1002/aja.1001890206

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

年代:1990

数据来源: WILEY

摘要:

AbstractRelaxin immunoreactivity was previously demonstrated in three cell types within the hamster placenta; fetal primary and secondary giant trophoblast cells (GTCs) and maternal endometrial granulocytes. The objectives of the present research were to examine the ultrastructure of the GTCs and identify the intracellular relaxin storage site. Primary GTCs, first present on day 8 of gestation, were characterized by numerous polyribosomes and large heterogeneous cytoplasmic inclusions suggesting phagocytic activity. Primary and secondary GTCs from days 10, 14, and 15 of gestation contained numerous polyribosomes, mitochondria with tubular cristae, an extensive Golgi complex, and abundant rough endoplasmic reticulum, all characteristics of a cell actively involved in protein synthesis. Membranebound secretory granules were not present. Relaxin was immunolocalized within the Golgi complex of primary and secondary GTCs using the avidin‐biotin‐peroxidase method. Following differential centrifugation of hamster placental homogenates and radioimmunoassay (RIA) of subcellular fractions, the majority of relaxin immunoactivity was detected in the postmicrosomal fraction; however, the majority of relaxin immunoactivity from similarly treated pig corpora lutea was present in the mitochondrial/granule fraction. These data indicate that hamster placental relaxin is not stored in membrane‐bound secretory granules but is contained within the extensive Golgi complex of th

ISSN:0002-9106    

DOI:10.1002/aja.1001890207

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

年代:1990

数据来源: WILEY

摘要:

AbstractMaxillary right first molar teeth of rats were tipped mesially with an orthodontic appliance for 2 weeks (experimental group),3H‐proline was injected, and orthodontic forces were removed 6 hr later (time 0). The contralateral molar teeth of treated (internal control group) and age‐ and weight‐matched untreated animals (external control group) were also studied. Diastemata were created between the molar teeth by the orthodontic appliance, and transseptal fibers between first and second (P<0.001) and second and third molars (P<0.005) were significantly lengthened as compared to external and internal controls at time 0. Diastemata between molar teeth were closed 5 days after removal of orthodontic force. Transseptal fibers adjacent to the source of the orthodontic force (mesial region) had the highest mean number of3H‐proline‐labeled proteins at time 0 and at all times following removal of the force (P<0.001), and had the highest rate of labeled protein removal (P<0.001). Half‐lives for removal of3H‐proline‐labeled transseptal fiber proteins were significantly greater in mesial and distal regions and significantly less in middle regions of experimentals than in corresponding regions of external controls (P<0.001). These data suggest the following: (1) transseptal fibers adjust their length by rapid remodeling in regions experiencing a tensile force; (2) collagenous protein turnover within the middle third of the transseptal fibers is more rapid subsequent to release of orthodontic force than during normal physiologic drift, suggesting that this region adapts rapidly to changes in adjacent tooth position and that these fibers do not play a significant role in relapse of orthodontically relocated teeth; and (3) significant differences in turnover rates of3H‐proline‐labeled transseptal ligament proteins of external and internal control quadrants suggest that tooth movement produces both local and systemic effects on collagenous

ISSN:0002-9106    

DOI:10.1002/aja.1001890208

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

年代:1990

数据来源: WILEY

ISSN:0002-9106    

DOI:10.1002/aja.1001890201

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

年代:1990

数据来源: WILEY