Anatomical Record最新文献

This essay lays the groundwork for the concept that "anatomy" in the new millennium will be a subject that is increasingly based on understanding the parallel relationships between systems of genes on chromosomes and the structures defined by these genes. The concept of Anatomic Genomics is introduced in terms of systems of genes on chromosomes, which actually mirror the biology of anatomically defined systems. A case is made for the possibility that genomes may be structured in ways that make local but not necessarily global sense. In the new millennium, systems biologists have the opportunity to be the creators and purveyors of this new anatomy.

Previous studies demonstrated that the main excretory duct (MED) of the rat submandibular gland can internalize exogenous protein in addition to reabsorbing and secreting electrolytes. However, more precise studies have not been conducted. The aim of this study was to elucidate the cell types responsible for endocytosis of an exogenous protein (ferritin) and to follow the movements of the endocytosed protein in the ductal epithelial cells. The MEDs of the right submandibular gland of male Wistar rats were exposed near the glands proper and cationized ferritin solution was injected into each MED through a fine glass cannula. The MEDs were removed at intervals after ferritin injection, fixed and examined by transmission electron microscopy. The epithelium of the MED of the rat submandibular gland was pseudostratified and consisted of light (types I and II), dark, tuft and basal cells. Uptake of ferritin by the light (types I and II) and dark cells occurred frequently. Small vesicles and multivesicular bodies containing ferritin particles were observed in the supra-nuclear and lateral nuclear cytoplasm. Endocytosis of tracers by tuft cells was rare. Some of the small vesicles and the multivesicular bodies were acid phosphatase-positive. By 60 min after treatment, ferritin-containing small vesicles and multivesicular bodies appeared in the basal cytoplasm. Ferritin particles were also observed in basal extracellular spaces. The light (types I and II), dark and tuft cells (latter rarely) participated in endocytosis of exogenous proteins in the epithelium of the MED of the rat submandibular gland. Almost all of the internalized proteins appeared to be processed by the lysosomal system, and some proteins were released into the extracellular spaces.

To help assess the immunological functions of the liver peritoneum, expression and 3D-microlocalization of adhesion molecules were studied by immuno-SEM and -TEM. The peritoneal tissues of the liver obtained from lipopolysaccharide (LPS, 1.5 microg/g BW for 24 hr)-stimulated (n = 18 including nine controls) and non-stimulated mice (n = 6 including three controls) were analyzed by immunolabeling with 15 nm gold particle single-labeling analysis of ICAM-1, ICAM-2, VCAM-1, MAdCAM-1, PECAM-1, ELAM-1, and CD105 expression. In addition, 10 and 20 nm gold particle double-labeling analysis of ICAM-1 and VCAM-1 was carried out with conventional TEM and BSE (backscatter electron) imaging. Gold particles detected in the peritoneal mesothelial cells were quantified using a computer analyzer, LUZEX III. Only ICAM-1 in non-stimulated mice and both ICAM-1 and VCAM-1 in LPS-stimulated mice were expressed on the mesothelium, but no other adhesion molecules were detected in either condition. Expression of ICAM-1 was consistently about four times greater than that of VCAM-1. Each adhesion molecule was restricted to the microvilli. ICAM-1 was expressed on all microvilli and tended to form clusters of three or four molecules. On the other hand, about 24% of the microvilli expressed VCAM-1 and less clustering was seen. Double-labeling techniques disclosed that VCAM-1 and ICAM-1 were rarely closely associated, usually spaced by about 40 nm. These results suggest that microvilli of the mesothelial cell play a significant role in leukocyte migration in the peritoneal cavity, by providing the important substrates for adhesion, ICAM-1 and VCAM-1.

Although chondroitin sulfate proteoglycans (CSPGs) are major components of the embryonic extracellular matrix, little attention has been paid to specific CSPGs in early heart development, in part because appropriate antibodies were not available. Therefore we prepared specific polyclonal antibodies against chicken aggrecan, versican, neurocan, and phosphacan. Western blotting and immunohistochemical studies revealed the presence of aggrecan and versican in stages 12-21 chicken embryo hearts in distinctive spatial and temporal patterns. Because this is the first demonstration of aggrecan in heart tissue, we further used RT-PCR to confirm that aggrecan is expressed in the heart and in situ hybridization to confirm the pattern of expression determined using antibodies. Versican is found in the myocardium and the myocardial basement membrane. In contrast, aggrecan is specifically colocalized with several groups of migrating cells including endocardial cushion tissue cells, epicardial cells, a mesenchymal cell population in the outflow tract that may be of neural crest origin, and a mesenchymal cell population in the inflow tract. The combined observations indicate that versican and aggrecan are expressed in unique patterns and suggest that they play very different roles in development.

We report the ultrastructural changes in acrosome morphology during the final steps of rat spermiogenesis, focusing on the relationship between the acrosome morphogenesis and the tubulobulbar complexes (TBC) development. During steps 18-19, the electron-lucent area in the dorsal cortex of the anterior acrosome gradually diminished, and finally, the acrosome became condensed and reduced its volume. Simultaneously with this tightening up of the acrosome, TBC developed from the head portion of late spermatids, protruding into the surrounding Sertoli cells. To investigate the incorporation of acrosomal contents into TBC, step 19 spermatids were stained by periodic acid-Schiff (PAS) reaction and by using the anti-acrosomal monoclonal antibody mMN7. Both PAS-reactivity and the mMN7-immunoreactivity were found in the TBC, as well as in the acrosome. In addition, the acrosome projected into the TBC-like structure, and materials of a density similar to that of the acrosome were observed in the core of the TBC. These results suggest that the TBC eliminate excess acrosomal contents prior to spermiation.

Morris (J. Anat., 1976;121:47-64) proposed that the subepicardial mesenchyme might represent a continuing source of myocardioblasts during embryonic and fetal development. Recent studies have shown that the epicardium and subepicardial mesenchyme, and the coronary vasculature are all derived from a region of the pericardial wall, called the proepicardial serosa. In avian embryos, the cells from the proepicardial serosa colonize the heart via a secondary tissue bridge formed by attachment of proepicardial villi to the heart. In the present study, Morris's hypothesis was tested by tracing the fate of the proepicardial serosa. This was achieved by constructing quail-chick chimeras. The proepicardial serosa was transplanted from HH16/17 quail embryos to HH16/17 chick embryos (ED3). A new transplantation technique facilitated an orthotopic attachment of the quail proepicardial villi to the chicken heart, and prevented the attachment of the chicken proepicardial villi to the heart. The fate of the grafted quail cells was traced in chimeras from ED4 to ED18 with immunohistochemistry, using quail-specific antibodies (QCPN, QH-1). From ED4 onward, the transplant was connected to the dorsal heart wall via its proepicardial villi. Starting from the point of attachment of the quail proepicardial villi to the heart, the originally naked myocardium became almost completely covered by quail-derived epicardium, and quail mesenchymal cells populated the subepicardial, myocardial, and subendocardial layers including the av-endocardial cushions. Quail cells formed the endothelial and smooth muscles cells of the coronary vessels, and the perivascular and intramyocardial fibroblasts. Quail myocardial cells were never found in the subepicardial, myocardial, and subendocardial layers. This suggests that the subepicardial mesenchyme normally does not contribute a substantial number of myocardioblasts to the developing avian heart. The new transplantation technique presented facilitates the production of chimeric hearts in which the derivatives of the proepicardial serosa are almost completely of donor origin. This technique might be useful for future studies analyzing the role of certain genes in cardiac development by the creation of somatic transgenics.

Early graft dysfunction after lung transplantation is a significant and unpredictable problem. Our study aimed at a detailed investigation of structure-function correlations in a rat isolated heart-lung model ofischemia/ reperfusion injury. Variable degrees of injury were induced by preservation with potassium-modified Euro-Collins solutions, 2 hr of cold ischemia, and 40 min of reperfusion. Pulmonary artery pressure (Ppa), pulmonary vascular resistance (PVR), peak inspiratory pressure (PIP), and perfusate gases (deltaPO2, deltaPCO2) were recorded during reperfusion. Right lungs were used to calculate W/D-weight ratios. Nineteen experimental and six control left lungs were fixed for light and electron microscopy by vascular perfusion. Systematic random samples were analyzed by stereology to determine absolute and relative volumes of lung structures, the amount of interstitial and intraalveolar edema, and the extent of epithelial injury. Lectin- and immunohistochemistry using established epithelial cell markers were performed in three animals per group to reveal sites of severe focal damage. Experimental lungs showed a wide range in severity of ischemia/ reperfusion injury. Intraalveolar edema fluid amounted to 77-909 mm3 with a mean of 448+/-250 mm3 as compared with 22+/-22 mm3 in control lungs (P<0.001). Perfusate oxygenation (deltaPO2) decreased from 30.5+/-15.2 to 21.7+/-15.2 mm Hg (P=0.05) recorded after 5 and 40 minutes of reperfusion. In experimental lungs, a surface fraction of 1% to 58% of total type I pneumocyte surface was damaged. Intraalveolar edema per gas exchange region (Vv ape,P) and deltaPO2 were related according to deltaPO2 = 96 - 60 x log10(Vv ape,P) [mm Hg]. The extent of epithelial injury did not correlate with deltaPO2 nor with intraalveolar edema, but increased significantly with PVR. Lectin- and immunohistochemistry revealed focal severe damage to the alveolar epithelium at the border of perivascular cuffs.