摘要:

AbstractHematopoietic colonies were studied by light microscopy in the marrow of alternate fraction x‐irradiated mice (C576J/B1) to investigate the microenvironmental organization of marrow and identify early hematopoietic cellstromal cell interactions. Undifferentiated colonies (UC) were detected at 3 days postirradiation, showed a marked predilection for bone surfaces, and disappeared as differentiated colonies developed. Some UC occurred along marrow arteries. Neutrophilic granulocyte colonies (GC) occurred in all areas at 3 days but grew rapidly only subosteally. Few eosinophilic colonies (GCe) occurred. Erythrocytic colonies (EC) appeared at 4 days as dispersed populations of motile cells within a localized area of marrow; these tended to proliferate initially in intermediate and central marrow zones. Macrophage colonies (MϕC) of two “subtypes” were detected, peaking in relative frequency at 4 days. These appeared active in stromal repair and monocytopoiesis. Megakaryocyte colonies (MC) originated along bone and differentiated away from bone. From 3–5 days, the frequency of GC>UC>MϕC ≫ MC ≅ GCe. All colony types except UC, MϕC, and central GC increased in size and became mixed in differentiation by 12–14 days. For several weeks, however, erythropoiesis concentrated toward central areas, whereas granulopoiesis and thrombopoiesis concentrated along bone. Some mixed colonies showed an abrupt transition from erythrocytic, centrally, to granulocytic, subosteally. These results were interpreted as evidence that in x‐irradiated marrow: (1) hematopoietic microenvironments (HMs) for stem‐cell proliferation and commitment to differentiation, with the possible exception of HMs determining erythroid differentiation, occur in endosteal and periarterial regions; (2) a proliferative and/or chemotactic stimulus to erythroid progenitors exists in intermediate and central marrow regions; and (3) some subosteal regions may exclude erythropoiesis, or preferentially support nonerythroid differentiation. Elaborate associations occurred between macrophages and early UC, GC, and EC, but not MC hematopoietic cells. UC and GC often associated with osteoclasts. Reticular and other fibroblastic cells associated with the cells

ISSN:0002-9106    

DOI:10.1002/aja.1001660402

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe capacity of the equine spleen to store and rapidly release as much as half the circulating blood volume after adrenergic stimulation depends upon the size of the spleen, its muscular capsule, and the distinctive structure of its red pulp. The unit, or lobule, of red pulp is a cylinder of pulp spaces organized in a reticular meshwork, supplied by a peripheral ring of arterial capillaries, and drained by a central venule. Reticular cells, which make up the meshwork of the pulp, contain an extraordinarily large complement of microfilaments and intermediate filaments and are richly innervated by nerves containing both dense and lucent core vesicles typical of adrenergic nerves. The wall of the pulp venule contains large apertures. The capacious red pulp would thus appear capable both of large‐scale blood storage and, by the contractile adrenergic innervated reticulum and open venous vasculature, of rapid expression of stored blood into the circulation.Antigen‐presenting cells are present not only in B and T cell zones in white pulp but in the periarterial macrophage sheath of red pulp as well. The periarterial macrophage sheath is one of the first sites of antigen capture, and the presence of these cells confers on it an immunological r

ISSN:0002-9106    

DOI:10.1002/aja.1001660403

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe distribution of cathepsin D (CD) was surveyed in rat tissues by light microscopic immunocytochemistry. Although immunoreactive CD was detected in all tissues examined, there was a marked difference in the amount in the cytoplasm of different cell types of the same organ. In the retina large amounts of CD were present in the pigment epithelium, ganglion cells, and Müller cells. Moderate to large amounts of CD were also found in neuronal perikarya of the gastrointestinal tract and adrenal medulla; in macrophages in the lung, liver, and spleen; in some secretory cells of the submandibular and lacrimal glands; in parts of renal distal convoluted and collecting tubules; and in the surface transitional epithelium of the calyx, ureter, and urinary bladder. Other cells adjacent to cells containing large amounts of the enzyme had little or no detectable CD themselves. These included hopatocytes, the proximal tubular cells of the kidney, selected cells of the submandibular gland, cells of the zona glomerulosa of the adrenal cortex, and lymphocytes in lymphoid organs. The localization of CD indicates that its degradative effect is exerted preferentially in certain cell types and suggests that physiological influences on CD may have a variety of effects in different organs

ISSN:0002-9106    

DOI:10.1002/aja.1001660404

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

年代:1983

数据来源: WILEY

摘要:

AbstractOvaries obtained from 18 adult, regularly cycling rhesus monkeys were evaluated to determine the status of preantral follicle development at various stages throughout the menstrual cycle. The ovaries were serially sectioned, and all preantral follicles on every 20th section were classified as developing or atretic, counted and/or measured, and grouped according to size.Results from this study revealed (1) that a significant increase (P100 μm in diameter during the periovulatory period, suggesting that follicles in this size range had developed a sensitivity to the unique hormonal milieu present during that stage of the cycle; (2) that similar numbers of primordial and developing preantral follicles were present in the right and left ovaries of a pair, showing that neither ovary had a predominance over the other; (3) that the mean number of developing preantral follicles varied directly with the size of the primordial follicle pool; (4) that atresia was minimal with no significant differences between the various stages of the cycle in any size group; and (5) that polyovular follicles were abundant in certain pairs of ovaries, but could not be related to age or stage of cycle

ISSN:0002-9106    

DOI:10.1002/aja.1001660405

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe method of embryonic tissue transplantation was used to confirm the dual origin of avian cranial sensory ganglia, to map precise locations of the anlagen of these sensory neurons, and to identify placodal and neural crest‐derived neurons within ganglia. Segments of neural crest or strips of presumptive placodal ectoderm were excised from chick embryos and replaced with homologous tissues from quail embryos, whose cells contain a heterochromatin marker. Placode‐derived neurons associated with cranial nerves V, VII, IX, and X are located distal to crest‐derived neurons. The generally larger, embryonic placodal neurons are found in the distal portions of both lobes of the trigeminal ganglion, and in the geniculate, petrosal and nodose ganglia. Crest‐derived neurons are found in the proximal trigeminal ganglion and in the combined proximal ganglion of cranial nerves IX and X. Neurons in the vestibular and acoustic ganglia of cranial nerve VIII derive from placodal ectoderm with the exception of a few neural crest‐derived neurons localized to regions within the vestibular ganglion. Schwann sheath cells and satellite cells associated with all these ganglia originate from neural crest. The ganglionic anlagen are arranged in cranial to caudal sequence from the level of the mesencephalon through the third somite. Presumptive placodal ectoderm for the VIIIth, the Vth, and the VIIth, IXth, and Xth ganglia are located in a medial to lateral fashion during early stages of development reflecting, respectively, the dorsolateral, intermediate, and epibranchial positions of these neurogenic

ISSN:0002-9106    

DOI:10.1002/aja.1001660406

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

年代:1983

数据来源: WILEY

摘要:

AbstractFollicular growth and kinetics were studied in detail in the ovaries of the Indian mole rat(Bandicota bengalensis)during various stages of the estrous cycle; days 7, 12, 15, 19, and 21 of pregnancy; and day 2 postpartum. The sizes of follicles, oocytes, nuclei, and nucleoli were measured. In all rats, regression coefficients, a, and intercepts, b, were calculated in oocyte/follicle, oocyte nucleus/follicle and oocyte nucleus/oocyte regressions. The oocyte reached its maximum size when the average follicle diameter was 117 μm in nonpregnant rats and 131 μm in pregnant rats. The oocyte nucleus attained maximum size when the follicle diameter was 110 μm during the estrous cycle and 111 μm during pregnancy and postpartum. Maximum values of the diameter of the largest antral follicle and average diameter of the four largest antral follicles were observed during proestrus (473 and 442 μm, respectively) and on day 21 of pregnancy (611 and 538 μm, respectively).X2analysis showed that distribution of various types of follicles was not independent of the stage of the estrous cycle and pregnancy. In estrus and metestrus most of the follicles were between stages I and V. However, by diestrus and proestrus, follicles of all size groups developed. The numbers of stage I and II follicles did not differ as pregnancy advanced. More stage V follicles were present on day 12 than on day 7 of pregnancy; however, their numbers decreased by day 15. Afterwards, progressive increase of stage V and (VI + VII) follicles was observed until day 21. This was accompanied by the shift of follicles from stage (III + IV) on days 19 and 21 of pregnancy and even of stage II on day 2 postpartum. Wherever possible, the results have been compared with previous observations in various rodent sp

ISSN:0002-9106    

DOI:10.1002/aja.1001660407

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe pineal recess of the Mongolian gerbil was studied using correlative scanning and transmission electron microscopy. The surface of the pineal recess can be subdivided into three distinct zones: (1) central, (2) transitional, and (3) peripheral. In the gerbil, the deep pineal gland is located deep to the central and transitional zones. The ependyma of the peripheral zone is densely ciliated and resembles that of the main ventricular lining. Ependymal cells of the transitional zone are sparsely ciliated but possess numerous microvilli on their apical surfaces. Supraependymal neurons were identified in the transitional zones. These cells appear to make a synaptic‐like contact with the underlying ependymal cells. Of the three zones, the central zone demonstrated the greatest amount of morphological variability. Although a number of supraependymal structures could be identified in the central zone, the most remarkable feature was the presence of protruding cells that possessed no significant surface features Employing correlative transmission electron microscopy, the protruding cells were shown to be CSF‐contacting pinealocytes. The number of CSF‐contacting pinealocytes present in the central zone varied from one cell to large clusters that covered the entire zone. The results of this investigation demonstrate the presence of a direct contact and the potential for interaction between the deep pineal gland and the CSF of the pineal recess in the g

ISSN:0002-9106    

DOI:10.1002/aja.1001660408

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

年代:1983

数据来源: WILEY

ISSN:0002-9106    

DOI:10.1002/aja.1001660401

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

年代:1983

数据来源: WILEY