摘要:

AbstractThe apical region of nonciliated cells of the ductuli efferentes of the rat contains tubular coated pits (TCP) connected to the apical plasma membrane, apical tubules (AT) which occasionally show a partial coat, and endosomes which are often continuous with one or more apical tubules. To investigate the formation and fate of TCP and AT, a quantitative analysis was performed on the labeling indices of these structures at various time intervals (0.5–120 min) after a single injection of a tracer, cationic ferritin (CF), into the lumen of the rete testis. The labeling indices of both TCP and AT exhibited similar cyclical patterns, first reaching a peak at 25 min, then dropping to a minimum at 35 min, then rising to a second peak at 60 min. Since TCP were well labeled at 30 sec while AT were not, the tracer must rapidly enter TCP and thence AT. However, since tracer was virtually absent from the lumen by 30 min, it was not possible to reconcile the second peak of labeling index of TCP and AT by this mechanism. In another experiment, rats were injected once as before, injected again at 30 min, and then sacrificed at 30 min following the second injection. The results from this experiment showed that the labeling index of TCP and AT did not drop but was similar to that of the 60‐min peak after a single injection. The interpretation is that there was recycling of tracer, which had already migrated from TCP to AT to endosomes, back to the apical plasma membrane via apical tubules. Moreover, when rats were injected once, injected again at 30 min, and sacrificed 3 min following the second injection, the labeling index for TCP and AT was significantly higher (P<.05) than at the 30‐min time interval after a single injection, indicating that recycled apical tubules were functionally capable of binding further CF. Morphological observations on images of transition between TCP and AT and the fact that AT were often found connected to endosomes suggest that TCP detach from the cell surface to give rise to AT, which in turn fuse to form endosomes. The kinetic analysis demonstrates in quantitative terms that a portion of the AT, which fuses to form endosomes, recycles back to the apical plasma membrane and contributes to the formation of ne

ISSN:0002-9106    

DOI:10.1002/aja.1001820202

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

年代:1988

数据来源: WILEY

摘要:

AbstractWe have localized horseradish peroxidase (HRP) in the mouse uterus after intravenous administration on days 1 and 5 of pregnancy in an effort to understand how serum proteins reach the uterine lumen. Direct movement of HRP into uterine and glandular lumina was blocked by the epithelial tight junctions on both days. In luminal and glandular epithelial cells at both times, HRP was localized in endocytic vesicles along the basolateral membranes, multivesicular bodies (mvb), elongated dense bodies below the nucleus (bdb), and many small vesicles near the apical surface of the cells. The uptake of HRP was most extensive in the luminal epithelium on day 1: the number of tracer‐containing apical vesicles and bdb was largest, and there were also clusters of vesicles containing the tracer above the nucleus. Acid phosphatase was localized on day 1 in mvb and bdb in both cell types, indicating that these structures are lysosomes. It appeared that HRP followed two pathways after basolateral endocytosis by the epithelial cells: it was transported to the apical region of the cells, where it was present in small vesicles that may release their contents into the uterine or glandular lumina, or it was transported to lysosomes.To investigate whether macromolecules may be transported from the uterine lumen to the stroma, we also studied endocytosis at the apical pole of luminal epithelial cells after intraluminal injection of HRP. There was no detectable uptake of HRP from the lumen on day 1, and no tracer was detected in the intercellular spaces or basement membrane region. On day 5, a large amount of HRP was taken up from the lumen into apical endocytic vesicles, mvb, and dense bodies, but tracer was not present in the Golgi apparatus, lateral intercellular spaces, or the basement membrane region at the times studied. These observations indicate that there was no transport of luminal macromolecules to the uterine stroma on day 1, while the possibility of transport on day 5 requires further stud

ISSN:0002-9106    

DOI:10.1002/aja.1001820203

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

年代:1988

数据来源: WILEY

摘要:

AbstractEctoplasmic specializations (ES) containing packed actin microfilaments are associated with the numerous parallel rows of occluding junctions which form the Sertoli cell (blood‐testis) barrier. To determine if ES regulate the structure of the occluding junctions and/or barrier permeability, we experimentally disrupted ES microfilaments in vivo with intratesticularly injected cytochalasin D (CD). Electron microscopic observations of seminiferous tubules from CD‐treated (150–500 μM CD; 0.5–12 hr) animals indicated that ES was absent from regions where the Sertoli cell barrier is located. Seminiferous epithelial sheets from uninjected or vehicle‐injected animals (1 DMSO: 1 saline) stained with NBD‐phallacidin demonstrated the presence of patterned ES actin surrounding the basolateral regions of adjacent Sertoli cells. After exposure to CD, epithelial sheets exhibited increasingly patchy fluorescence indicating progressive F‐actin disruption. Freeze‐fracture replicas of CD‐injected testes revealed numerous focal alterations in the region of occluding junctions which included disorganization of the parallel arrangement of junctional rows, the presence of free‐ending rows, clustering of intramembranous particles (IMPs) between rows, reduction in the number of rows, and loss of IMPs on both the P‐face and E‐face. Tracer experiments, following CD exposure, were conducted to test the integrity of occluding junctions: lanthanum hydroxide, dextrose, or filipin was added, in separate experiments, to the fixative during perfusion‐fixation. In another study, serum containing an antibody against adluminal germ cells was injected intratesticularly, and frozen sections were processed for immunofluorescence study. A final study consisted of simultaneous intratesticular infusions of CD and radiolabelled inulin with subsequent intraluminal and peritubular fluid sampling. In animals which were injected with CD, lanthanum was found to enter the adluminal compartment; fixative made hypertonic by addition of dextrose caused germ cells within the adluminal compartment to shrink and produce exaggerated intercellular spaces; filipin‐cholesterol perturbations were present between some Sertoli cell junctional rows and on spermatid plasma membranes; and IgG was detected within the adluminal compartment of many seminiferous tubules. None of these adluminal manifestations was noted in control animals or those which received vehicle. Quantitatively, in the in vivo micropuncture experiments, significantly more radiolabelled inulin entered the lumen of seminiferous tubules from CD‐treated animals than from those exposed to vehicle. Collectively, the data suggest that CD treatment alters the functional integrity of the Sertoli cell barrier and that this may be the result of disruption of microfilamen

ISSN:0002-9106    

DOI:10.1002/aja.1001820204

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

年代:1988

数据来源: WILEY

摘要:

AbstractCBA/N mice carry an X‐linked immune‐deficiency gene, leading to a defect in the ability to form antibodies against T‐independent type 2 antigens. By using immunohistochemistry, the organization of the spleen of the immune‐deficient male (xid) CBA/N F1 and the normal female F1 were compared. Staining with antilymphocyte markers showed that the total number of cells in the various T‐ and B‐cell areas was smaller in thexidmouse, resulting in very small white pulp compartments. Fewer B cells were seen in the marginal zone. When the spleens of the F1 mice were examined for macrophage markers, the rings of marginal‐zone macrophages and the ring of marginal metallophilic macrophages were much thinner in thexidmouse. In particular, the marginal‐zone macrophages are thought to play a role in the response against thymus‐independent type 2 antigens, and their small numbers in thexidmouse are suggestive of a role for the microenvironment in the defe

ISSN:0002-9106    

DOI:10.1002/aja.1001820205

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe developmental morphology of the hypoglossal nerve and associated structures were studied in the chick embryo (Hamburger and Hamilton stages 16‐27) stained by the immunohistochemical technique. Ventral rootlets of the occipital nerves, including 01, were seen at stage 16. The distal ends of these nerves anastomosed to form the hypoglossal nerve at stage 20. At stage 23, four occipital and the first three cervical nerves were observed to be involved. The transient contribution of C3 at this stage seemed to be correlated with the formation of the longitudinal anastomosis of the distal end of the spinal nerves which begins around stage 23. The anterior hypoglossal roots appeared between 01 and the abducens nerve at stage 20. These rootlets were observed to arise as the rostral continuation of the occipital sequence and were found to be arranged in a straight line from 01 to the abducens nerve. The recurrent branch of the abducens was also observed. The posterior end of the ganglion crest produced dorsal root ganglion (DRG)‐like structures transiently at the level of C2, and sometimes at the level of C1 also. The ganglion crest developed descending processes in the occipital region seemingly related to the spinal dorsal root formation. These phenomena seemed to represent the potential of the ganglion crest to produce the spinal nerve components which are depressed in the occipital reg

ISSN:0002-9106    

DOI:10.1002/aja.1001820206

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe development of the facial nerve from Hamburger and Hamilton stage 17 to stage 28 is described in chick embryos by means of a new immunochemical nerve staining method that uses an antineurofilament protein (NFP) antibody. A postspiracular branch and an unknown transient posterior branch beneath the ostocyst were observed at stage 17. At stage 19, the primordia of the r. palatinus were observed. A prespiracular branch appeared at stage 21, and with the postspiracular nerve, it made a loop encircling the spiracle (spiracular loop). The first primordium of the ramus (r) hyoideus and transient rami (rr) dorsales appeared around stage 23. At stage 25, the chorda tympani was first observed to arise from the ventral end of the spiracular loop. At stage 26, a communicating branch, connexus cum nervo glossopharyngeo, was found along with the vena (v) capitis lateralis.The rr. dorsales seemed to represent the r. supratemporalis in lower animals. The communicating branches around the v. capitis lateralis seemed to correspond to the cutaneous nerve communications between the branchial nerves frequently encountered in Amphibia.It was found that the chorda tympani becomes a prespiracular nerve for the most part in the chick by the reduction of the postspiracular component of the spiracular loop. Thus, the nerve differs markedly from that in other animals, which is postspiracular. This difference explains the different passage of this nerve in the chick as compared with other amniotes.

ISSN:0002-9106    

DOI:10.1002/aja.1001820207

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe development of the vasculature of the pectoral fin in the Australian lungfish,Neoceratodus forsteri, was studied by the dye‐injection method. Only a single primitive subclavian artery appears from the dorsal aorta for the fin anlage, and it passes laterally through the postaxial region of the structure. The venous channel draining into the posterior cardinal vein is located in the preaxial region medially. As development proceeds, the arteriovenous arrangement in the pectoral fin anlage changes as follows: (1) one artery and one venous plexus, (2) two arteries and one vein, (3) three arteries and one vein, (4) four arteries and one vein, (5) three arteries and two veins, and (6) two arteries (radial and ulnar) and three veins (radial, ulnar, and ulnar marginal).The fin anlage through embryonic first rotation has gradually changed its postaxial margin to face dorsally and its preaxial margin to face ventrally. The second rotation causes the original preaxial margin to become dorsal and the original postaxial margin to become ventral. As a result, the radial and ulnar arteries are observed in the dorsal and ventral regions, respectively, in the medial side of the fin instead of in the lateral side as seen in the previous stag

ISSN:0002-9106    

DOI:10.1002/aja.1001820208

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

年代:1988

数据来源: WILEY

ISSN:0002-9106    

DOI:10.1002/aja.1001820201

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

年代:1988

数据来源: WILEY