摘要:

AbstractBlood vessels of the human telencephalic germinal matrix during the tenth through the twenty‐second week of gestation have been examined by light and electron microscopy. In all fetuses studied the ependymal and sub‐ependymal zones of the germinal matrix have a prominent vascular network. During the tenth and twelfth weeks of gestation, the endothelial cells are plump and display numerous organelles, junctional complexes, conspicuous luminal microvilli and stub‐like abluminal projections. Coated and micropinocytotic vesicles were found both in the cytoplasm and on luminal and abluminal surfaces. In endothelial cells intracytoplasmic, membrane‐limited, rod‐shaped bodies were frequently observed. These bodies have been linked to endothelial thromboplastic and clotting activities and related to abnormal clotting status. Their role in the pathogenesis of subependymal germinal matrix hemorrhage in premature infants remains unknown. Pericytes apposing the endothelial cells were recognized in all gestational periods. The endothelial basal lamina and astrocytic end‐feet are ill defined, and the extracellular space is pronounced. By the fifteenth and seventeenth weeks of gestation the endothelial cells are still large and now possess more numerous luminal microvilli and abluminal projections. At this stage the pericytes, basal lamina and astrocytic end‐feet are all well developed, resulting in a decrease in the surrounding extracellular space. By the twenty‐second week the endothelial cells possess few luminal and abluminal projections and the associated basal lamina, glia, pericytes and extracellular compartment appear mature. The relationship of the germinal matrix vasculature to the pathogenesis of subependymal hemorrha

ISSN:0002-9106    

DOI:10.1002/aja.1001490402

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

年代:1977

数据来源: WILEY

摘要:

AbstractCalvariae of fetal mice 12 to 13 daysin uterowere placed in Rose chambers and cultured in BGJb medium supplemented with 20% fetal calf serum and antibiotics. After periods of 7 and 12 days, the explants were harvested and processed for light and electron microscopy. The mesenchymal cells, after a brief lag time, differentiated into osteoblasts which produced woven bone. Light and electron microscopic observations showed that in vitro, as well as in vivo, growth and development share all of the same characteristics of initial intramembraneous osteogenesis: (1) migration and differentiation of mesenchymal cells into osteoblasts, (2) the subsequent appearance of matrix vesicles in the extra‐cellular space, (3) crystallization of hydroxyapatite within and about these vesicles, (4) growth of hydroxyapatite crystals into spheroidal nodules of bone, and (5) the subsequent fusion of these nodules into seams of woven bone. Thus cellular involvement in initial osteogenesis has been observed in a system where differentiation into osteoblasts and initial calcification takes place in vitro, suggesting that the events responsible for these phenomena have occurred within the cells prior to their morphological differentiatio

ISSN:0002-9106    

DOI:10.1002/aja.1001490403

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

年代:1977

数据来源: WILEY

摘要:

AbstractA daily rhythm was demonstrated in levels of specific activity for the Na, K‐ATPase and glucose‐6‐phosphatase enzymes in adrenal and renal subcellular fractions in the rat. A bimodal daily rhythm was observed for 5′‐nucleotidase in a renal subcellular fraction. The rats were maintained on a 12:12 light‐dark (LD) regimen. Animals were killed at approximately 4‐hour intervals.The daily rhythm in Na, K‐ATPase and glucose‐6‐phosphatase activities persisted in animals maintained under continuous illumination (LL) and continuous darkness (DD). The 5′nucleotidase activity persisted under LL, and under DD.The data from the enzyme assays were analyzed by fitting to a cosinor regression model designed to assess the rhythmic nature of the findings. A linear transformation method was applied to assess the closeness of fit to the cosinor regression model.The Na, K‐ATPase and glucose‐6‐phosphatase activities appeared to be endogenous circadian rhythms. Glucose‐6‐phosphatase activity in renal fractions appeared to be influenced by the feeding cycle. The 5′‐nucleotidase enzyme appeared to have an ultradian rhythm. The ultimate derivation and significance of these observed rhythms remains to be determined; however, they appear to be

ISSN:0002-9106    

DOI:10.1002/aja.1001490404

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

年代:1977

数据来源: WILEY

摘要:

AbstractIn the rat the size distributions of cell bodies in the trigeminal motor nucleus and of myelinated fibers in the portio minor were bimodal. The size distribution of mesencephalic nuclear somata was unimodal. The number of fibers in the portio minor was approximated by the number of somata in the motor and mesencephalic nuclei. Within the motor nucleus large and small cells were chromatolytic after destruction of the portio minor. Injections of horseradish peroxidase (HRP) into the masseter and temporalis muscles labeled both the large and small neurons in the dorsolateral part of the nucleus. Similar injections into the anterior belly of the digastric and mylohyoid muscles labeled neurons in the ventrolateral part of the nucleus, but these neurons were not among the smallest in the nucleus. Within the mesencephalic nucleus chromatolytic somata occurred only ipsilaterally after unilateral lesions of the portio minor, and in lesser numbers after destroying the portio major. Unilateral injections of HRP into the masseter and temporalis muscles labeled cells in the ipsilateral mesencephalic nucleus and trigeminal ganglion. Labeling of mesencephalic neurons was abolished by lesions of the portio minor. Similar injections into the anterior belly of the digastric and mylohoid muscles labeled cells in the ipsilateral trigeminal ganglion, but not in the mesencephalic nucleus. These results are discussed in light of previous work on the trigeminal system.

ISSN:0002-9106    

DOI:10.1002/aja.1001490405

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

年代:1977

数据来源: WILEY

摘要:

AbstractMyocytes of the heart of the newborn rat are mononucleated, whereas myocytes of the heart of growing, maturing rats become predominantly binucleated. This appears to be explained by mitotic division shortly after birth without cell division, i.e., karyokinesis without cytokinesis. Myocytes isolated from hearts of adult guinea pig and pigeon are also predominantly binucleated. Although only about an eighth of the cells of adult rat hearts are myocytes, most of the increase in size of the heart from birth to six months can be accounted for by change in size of these cells.

ISSN:0002-9106    

DOI:10.1002/aja.1001490406

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

年代:1977

数据来源: WILEY

摘要:

AbstractThe monkey epididymis was subdivided into four regions: initial segment (continous with the ductuli efferentes), head, body and tail. The initial segment possesses a very tall columnar epithelium (108 ± 4 μm). Epithelial height in the head, body and tail is diminished to 81 ± 5 μm, 69 ± 2 μm, and 50 ± 5 μm, respectively. The pseudostratified epithelium is composed of four main cell types: principal, apical and basal epithelial cells, and intraepithelial lymphocytes. Occasional macrophages are also found in the epithelium. The tall, narrow, columnar principal cells demonstrate morphological features characteristic of absorption and secretion. An unusual feature, apparently unique to the primate, is the presence of deep invaginations of the apical cytoplasm which contain membrane‐bounded vacuoles. Similar, but larger vacuoles are present among the stereocilia and in the tubular lumen. Large clusters of mitochondria and electron‐dense membrane‐bounded granules characterize the infranuclear region of the cytoplasm. Principal cells are studded with closely aligned stereocilia. Their nuclei are spindle‐shaped in the initial segment and first portion of the head region, but become highly infolded in the distal head, body and tail portions. The apical or mitochondrion‐rich cells possess a cytoplasm which extends from the base of the epithelium to the tubular lumen. Basal cells contain few organelles and are found throughout the length of the duct. Arterioles and capillaries appear to penetrate directly into the epithelium from the underlying connective tissue; however, the basal lamina of the epididymal duct always intervenes between the endothelium of the blood vessels and the epithelial cells. Several of the above observations have not been noted in rodents and other mammalian species and may be uniq

ISSN:0002-9106    

DOI:10.1002/aja.1001490407

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

年代:1977

数据来源: WILEY

摘要:

AbstractYoung adult male rats were treated with clomiphene citrate, a non‐steroidal inhibitor of gonadotropin release in the rat. They were administered 2.5, 3.5, or 5.0 mg/100g/day for intervals up to 12 weeks. The weights of the sex accessory glands were less than those of control rats, and decreased with increasing dose and length of treatment. At the longer intervals, the weights of the testis and epididymis were also less than those of control animals. Microscopic alterations in the testis included a scarcity or even absence of late spermatids, the presence of necrotic cap‐phase spermatids, and accumulation of lipid droplets and large lysosome‐like structures in Sertoli cells. In rats treated for the longest interval, 12 weeks, testicular changes were even more extensive; degenerating primary spermatocytes were observed, and in one rat germ cells were virtually completely absent and the seminiferous tubules were occupied by Sertoli cells. The Leydig cells of treated animals were smaller than those of normal or control rats. Sperm were absent from the lumen of the caput epididymidis in most specimens. Although the epithelium of the caput appeared reduced in height in some samples, ultrastructural changes in cellular organelles were not detected. In most specimens of the cauda epididymidis, the lumen was small, irregularly shaped, and lacking in sperm. Light cells were prominent in the epithelium by virtue of their content of many apical vacuoles and dense granules. In some specimens of the distal cauda epididymidis, the duct had a circular profile and the lumen contained round cells and debris. The seminal vesicle and the ventral prostate were greatly suppressed. The normally tall columnar epithelia were reduced to a low columnar or cuboidal shape. Especially at the longer treatment intervals, the normally abundant rough endoplasmic reticulum was sparse, and in some samples secretory vacuoles were absent. The possible mechanism of production of these morphological changes is discussed, and the results are compared with those following treatment with other antifertility agents, including cyproterone acetate, a progestin, and a progestin‐androgen

ISSN:0002-9106    

DOI:10.1002/aja.1001490408

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

年代:1977

数据来源: WILEY

摘要:

AbstractWhen a single sublethal dose (300 mg/kg body weight) of cyclophosphamide was injected intraperitoneally into experimental mice, several morphological alterations were detected in the crypt epithelium within a few hours. These were (a) mitotic activity of epithelial cells decreased, reaching the lowest level at 16 hours; (b) an abnormally high number of lymphocytes and cells with eosinophilic granules appeared in the epithelium; later these cells degenerated and the maximum number of dead cells was observed at six hours after the drug injection. At four days post‐injection the morphology of crypt epithelium had returned to normal.Electron microscopic examination revealed that although the mitotic activity of crypt epithelial cells was depressed, there was little change in their morphology following the drug administration. However, many intermediate stages of degeneration of lymphocytes and eosinophilic cells were observed in the intercellular spaces as well as apparently inside the cytoplasm of crypt epithelial cells. The eosinophilic cells are characterized by the presence of large crystal‐containing granules in the cytoplasm, and are believed to be equivalent to “globular leucocytes” described by many investigators. Evidence from this study suggests that lymphocytes and globular leucocytes are more sensitive to cyclophosphamide than crypt epithelial cells, and that they degenerate in crypt epi

ISSN:0002-9106    

DOI:10.1002/aja.1001490409

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

年代:1977

数据来源: WILEY

摘要:

AbstractIn rat pancreatic islets, the glucagon‐producing A‐cells also contain a GIP‐like material as revealed by the peroxidaseantiperoxidase immunocytochemical technique. Control studies showed that this dual staining was not due to the cross‐reactivity of anti‐GIP with glucagon. It is concluded either that the A‐cells synthesize a GIP‐like peptide or that it is taken up from th

ISSN:0002-9106    

DOI:10.1002/aja.1001490410

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

年代:1977

数据来源: WILEY

摘要:

AbstractFollowing multiple tooth pulp extirpations, electron microscopic preparations show degenerating axons and synaptic terminals in the same region of the brain stem trigeminal nucleus previously demonstrating degeneration by light‐optical methods. The observations confirm the phenomenon of transganglionic degeneration in this system and identify the class of central nervous system axons and synapses specifically related to innervation of the teet

ISSN:0002-9106    

DOI:10.1002/aja.1001490411

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

年代:1977

数据来源: WILEY