摘要:

AbstractLavaged alveolar macrophages of mice were examined by light and electron microscopy primarily using cytochemical reactions for lysosomal enzymes. Among several methods tried, the Reed and Bennett procedure for N‐acetyl‐β‐glucosaminidase (J. Histochem. Cytochem.,23:752–757 (1975)) was preferred for use in smears and the Gomori acid phosphatase method for ultrastructural study. Prior to examination, some mice were exposed to an aerosol of finely divided iron oxide for 1–3 hours at particle concentrations of 80–290 mg/m3, others breathing clean air provided macrophages for comparison. Both exposed and unexposed macrophage populations were composed of a similar range of subtypes differing in cytological appearance and enzymic activity. The exposed populations tended to contain a higher proportion of strongly reactive cells, notably of a kind possessing many elongate lysosomes; consequently, it appeared that many cells in these populations were substantially engaged in synthesizing lysosomes. Based on this material, the cycle of production was reconstructed. This is divisible into five natural stages, defined primarily by the intracellular distribution of lysosomal enzyme activity and to a lesser extent by other cytological criteria. Commencing in immature cells, where the predominant localization of acid phosphatase activity in the Golgi apparatus and a few rounded lysosomes (Stage 1), the cycle continues through a period dominated by extensive growth of the granular endoplasmic reticulum (Stage 2). With the appearance of a crop of elongate or lumbricoid lysosomes, the predominate locus of acid phosphatase activity shifts from the Golgi apparatus to these bodies (Stage 3). Thereafter, they often are seen together with an increased number of large rounded lysosomes (Stage 4), but in other cells only the latter are to be found (Stage 5). This lysosomal cycle operates in cells showing other signs of an aroused metabolism, and it appears not to be closely tied to the mitotic cycle. The nascent lumbricoid lysosomes seem to be formed at some distance from the Golgi apparatus, wheras the lysosomes produced by more quiescent cells often lie in close relationship to th

ISSN:0003-276X    

DOI:10.1002/ar.1092060203

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

年代:1983

数据来源: WILEY

摘要:

AbstractIntracytoplasmic interactions were examined in iron oxideexposed and ‐unexposed alveolar macrophages of mice by electron microscopy and ultrastructural cytochemistry. Submicronic‐sized particles are taken up by microendocytosis into 800‐Å tubules that sometimes open up into a large vacuole located midway between the plasmalemma and the Golgi complex and sometimes lead directly to that organelle, which is reactive for acid phosphatase while cells are only modestly engaged in lysosomal synthesis and then serves as the main locus for formation of heterolysosomes. In more activated cells, nascent lumbricoid lysosomes are budded directly off branches of the granular reticulum; in consequence, much of the newly synthesized acid phosphatase bypasses the Golgi apparatus, and heterolysosomes are formed throughout a widened expanse of cytoplasm. The lumbricoids exist either as free elements or as a labyrinthian network of lumbricoid units, and the two forms appear interconvertible. They are short lived in contrast to larger rounded lysosomes more commonly present, many of which are heterolysosomes as judged by their content of ingested particles. Lumbricoids readily fuse with exoplasmic structures; indeed, in some lumbricoid‐producing cells terminal segments of the reticulum may share this propetry to a degree, since they resemble transitional elements when extended along large phagosomes. Microendosomes can be taken up into lumbriciods, but if the endosome is larger, lumbricoids will adhere to its surface and become part of the digestive vacuole. A labyrinth is formed to envelop large phagosomes or regions of cytoplasm marked for autophagy. The interior is invaded by branches and digestion ensues. In active macrophages the Golgi apparatus is enlarged. The centrioles organize an array of microtubules about themselves, and individual Golgi stacks are turned outward to give the organelle better access to phagosomes and lysosomes. In less active cells the microtubules disappear, and the stacks reform in a circle about the diplosome. Alveolar macrophages therefore make a variety of lysosomes. Depending on cellular activity, one kind or another predominates. Few of them fall cleanly into “primary” and “secondary” classes, and in their interactions with other cellular structures they are influenced by mechanisms operating on microscopic as well as

ISSN:0003-276X    

DOI:10.1002/ar.1092060204

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

年代:1983

数据来源: WILEY

摘要:

AbstractBoar spermatozoa were observed by a rapid‐freeze, deep‐etch, and rotary shadowing technique. Domains of particles were found on the ES face of the plasma membrane in the proximal part of the postacrosomal region. Particles are 17 nm in diameter, have a central pit, and appear to contain either five or six subunits. The diameter of the subunits is about 7 nm. The particles are arranged hexagonally within the domain. Straight parallel ridges, 15 nm wide, were found on the entire PF face of the plasma membrane in the postacrosomal region. The ridges run almost parallel to the long axis of the spermatozoon. Part of the postacrosomal sheath could be seen through artificial openings in the PF face of the plasma membrane. The postacrosomal sheath seems to be a sheet of closely packed particles 7 nm in diameter and has striations with a periodicity of 15 nm. The ridges on the PF face of the cell membrane appear to be reflected by the striations of the postacrosomal sheath. In the neck and tail regions of the spermatozoa, orderly arranged particles were observed on the ES and PF faces of the plasma membr

ISSN:0003-276X    

DOI:10.1002/ar.1092060205

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

年代:1983

数据来源: WILEY

摘要:

AbstractA granular cell was present at the acinar‐intercalated duct junction in submandibular gland of adult rats of several different strains. It occurred more frequently in females thanin males. It was a small pyramidalshaped cell, usually forming the most proximal part of the intralobular duct system. The cell contained a relatively large, basally located nucleus. Numerous heterogeneous granules, usually exhibiting both electron‐dense and electron‐lucent regions, were present in the apical cytoplasm. Exocytosis of the granules at the apical cell surface was occasionally seen. Dilated cisternae of endoplasmic reticulum were frequently observed between the apical granules and in the basal and lateral cytoplasm. The function of the granular cell is unknown. Their structure and location suggest that they may (1) constitute a mature secretory cell population, or (2) represent progenitor cells for acinar and/or intercalated duct

ISSN:0003-276X    

DOI:10.1002/ar.1092060206

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

年代:1983

数据来源: WILEY

摘要:

AbstractIn order to study the localization pattern of specific antibody‐containing cells and extracellular antibody in the spleen during a primary immune response, the antigen human serum albumin (HSA) was injected intravenously in rabbits, either free in solution, or associated with the surfaces of liposomes as a model of membrane‐associated antigens. Demonstration of specific antibody‐containing cells was performed by incubation of sections of spleen with HSA‐HRP conjugates, followed by peroxidase cytochemistry.Specific anti‐HSA antibody‐containing cells were detected already at 4 days after injection of the antigen. The bulk of these cells localized initially in the outer parts of the periarteriolar lymphocyte sheaths (PALS) and around the terminal arteriolar branches. Both extracellular antibody and specific antibody‐containing cells were also found in the follicles of the spleen. Arguments are given that extracellular antibody precedes the development of specific antibody‐containing cells in the follicle. This extracellular antibody probably represents antigen‐antibody complexes trapped in the follicles as soon as the antigen in the circulation is complexed by the first antibodies produced during the immune response. The localization pattern of specific antibody‐containing cells and extracellular antibody did not differ markedly when rabbits injected with free or liposome‐associated antigen were compared. Results are discussed particularly with respect to the role of follicles i

ISSN:0003-276X    

DOI:10.1002/ar.1092060207

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

年代:1983

数据来源: WILEY

ISSN:0003-276X    

DOI:10.1002/ar.1092060208

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

年代:1983

数据来源: WILEY

摘要:

AbstractSeptation of the cardiac truncus arteriosus in the normal rat embryo was described and illustrated by three‐dimensional reconstruction from serial sections through the developing outflow tract. Tracings of selected structures were digitized on an Apple II‐plus microcomputer, relayed through a central computer facility, and displayed on a Hewlett‐Packard 9845C graphics computer. Rotation and dissection of the color images allowed a kinetic description of the principal features of truncal septation and comparison with analogous events in the chick.A complex of tissue structures appeared in the downstream, distal truncus at 13 days of gestation and moved toward the ventricle(s) through the following day. As in the chick, the forming semilunar valves remained within 200 μm of the cephalic margin of the myocardial sleeve as they rotated and descended toward their definitive position against the heart. Mesenchymal condensations formed within the intervening aorticopulmonary (AP) septum and remained in close association with the principal bifurcation of the spiralling blood lumens, passing between the valves and descending along the conus septum. As the conus septum fused at 15 days of gestation, three outlets for cardiac outflow were seen: the major left and right streams to the aortic and pulmonary valves, respectively, and an apparently dwindling stream which crossed from the right ventricle behind the conus septum to exit through the aorta. In the chick, but not in the rat, nerve bundles invaded the distal truncus during septation to form the cardiac

ISSN:0003-276X    

DOI:10.1002/ar.1092060209

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

年代:1983

数据来源: WILEY

摘要:

AbstractA bipolar cell type with a dendritic span in the outer plexiform layer (OPL) larger than any other type of monkey retinal bipolar cell and an axon which terminates in two separate strata (Polyak's 7a and 7d) of the inner plexiform layer (IPL) are described from Golgi‐impregnations of the rhesus monkey retina. These giant bistratified bipolar cells connect with many cones in the OPL, and although the axon has terminals in both the outer and inner parts of the IPL, Golgi‐electron microscopy (EM) demonstrates that the nature of this cell type's dendritic contacts with cones is as wide‐cleft basal junc

ISSN:0003-276X    

DOI:10.1002/ar.1092060210

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

年代:1983

数据来源: WILEY

摘要:

AbstractA novel sectioning technique for making serial sections for use in descriptive embryology is presented. This technique allows one to obtain good‐quality sections (5‐ to 10‐μm thick) of embryos embedded in plastic, several times faster than with conventional plastic sectioning techniques. Furthermore, this technique can be used to serially section embryos until desired levels are reached. One‐micrometer or thin (50–100 nm) sections can then be cut for study, respectively, by light and transmission electron microscopy. The resolution of cellular morphology in 5‐ to 10‐μm sections is intermediate to that of paraffin and 1‐μm plastic sections, and gross tissue distortions typically present in paraffin sections are absent in plastic sections. Thus, in terms of convenience and section quality, this technique bridges the gap between those routine techniques used for preparation of conventional paraffin and plast

ISSN:0003-276X    

DOI:10.1002/ar.1092060211

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

年代:1983

数据来源: WILEY

摘要:

AbstractComparative critical examination of methods suitable for studying stress in bones have shown that the three‐dimensional photoelastic method is one of the most reliable. Described herein is the method for obtaining, by fusion, full‐scale models in epoxy resin, that are exactly equivalent to external shape of the prototypes.This technique offers the advantages of being applicable without variation to any bone segment and of enabling a large number of additional resin castings to be made from the same mould. Hence it is possible to produce a very large number of copies of the same bone segment that will be suitable for comparative studies of different load situations.As an example, quantitative data expressing both surface and internal tension trends in the proximal third of a normal human femur are gi

ISSN:0003-276X    

DOI:10.1002/ar.1092060212

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

年代:1983

数据来源: WILEY