Postasphyxial management of the newborn.

In this article, postasphyxial management of the newborn is reviewed. Emphasis is placed on the multisystem approach to complications that can occur in an infant who has sustained significant hypoxia and ischemia. The frequently involved organs are reviewed individually with respect to specific complications that arise secondarily to the initial injury. Depending on the severity of damage to the organ, therapeutic interventions are frequently required; however, medical management is often limited to supportive measures and serial evaluations.

Correlation of extracellular matrix components with the cytoarchitecture of mouse Peyer's patches.

The distribution patterns of extracellular matrix elements were determined to ascertain whether they play a role in the localization of lymphocytes in discrete T-cell, B-cell and dome antigen-processing domains within Peyer's patches. Antibodies against collagen types I, III and IV, laminin and fibronectin were applied to cryosections of mouse Peyer's patches and localized by direct or indirect immunoperoxidase methods. T-cell domains were identified with a monoclonal antibody against Thy-1.2. Labeled reticular fibers in distinctive patterns were more numerous in parafollicular and dome areas than within follicles. Germinal centers contained few such fibers. In parafollicular areas, fibers were oriented predominantly toward follicle domes; their distribution corresponded to T-cell zones and lymphocyte traffic areas, with their orientation being parallel to the migration pathways of lymphocytes from high endothelial venules to the antigen-processing domes. Subepithelial and subendothelial basal laminae were immunopositive for type-IV collagen, laminin and fibronectin. The dome subepithelial basal lamina had pore-like discontinuities through which lymphocytes migrated to and from the epithelium. The correspondence of the distribution patterns of extracellular matrix to specific functional domains of Peyer's patches suggests that this matrix provides a structural framework for lymphocyte migration and localization.

Ultrastructural and cytoarchitectural features of lymphoreticular organs in the colon and rectum of adult BALB/c mice.

The structure and function of colonic mucosal lymphoid organs remain largely unexplored, especially in the rectum hidden within the pelvic vault. Two-month-old female BALB/c mice were anesthetized, and the entire colon was removed from cecum to anus. Distal colonic patches were then prepared for electron microscopy or were quick-frozen and sectioned for immunoperoxidase localization of B cells and T cell subsets. Aggregated lymphoid follicles were distributed irregularly along the entire colon with an average of 1.4 patches per centimeter of colon length. There were large collections of follicles opposite the ileocecal valve (cecal patches), variable numbers of patches throughout the colon, and at least one patch within 10 mm of the anus (rectal patch). Follicles were adjacent to branching crypts lined by epithelium infiltrated by lymphoid cells and containing few goblet cells. In electron micrographs, M cells were identified by their short, irregular microvilli; intraepithelial lymphoid cells; reduced lysosomal dense bodies; and an expanded tubulovesicular network. Small germinal centers were seen. Cytoarchitectural components of colonic lymphoid follicles and Peyer's patch follicles were remarkably similar, despite differences in surrounding mucosa and luminal microbial exposure. The presence of organized lymphoid tissue with M cells and germinal centers suggests that transepithelial particle transport and antigen recognition can take place in the rectum. Whether such tissue has the capacity for uptake of luminal microorganisms is of particular interest, not only because colonic follicles may be sites for local initiation of immune responses but also because they may be important entry points for systemic infection.

Interactions of human colorectal carcinoma cells with basement membranes. Analysis and correlation with differentiation.

The abilities of colorectal carcinoma cell lines to adhere and invade through a basement membrane were examined. The four poorly differentiated cell lines studied were three to four times more adherent and spread to a greater extent following adherence to a basement membrane matrix than the three moderately well-differentiated (MWD) lines. One exception was the MWD cell line DLD-2, whose histologic features resembled a signet ring carcinoma. The ability of these cells to invade through a basement membrane model was measured. This assay showed that the poorly differentiated cell lines as well as DLD-2 were three times more invasive than the remaining MWD cell lines. These data indicate that tumor cell adherence can be correlated with invasion through basement membranes. In addition, the ability of colorectal carcinoma cells to interact with the basement membrane seems, in general, to be inversely related to the degree of cytodifferentiation.

Relationship between extracellular matrix interactions and degree of differentiation in human colon carcinoma cell lines.

Human colon carcinoma cell lines that vary in their degree of differentiation were examined for their ability to interact with extracellular matrix components. For this purpose, established cell lines were classified on the basis of several criteria that relate to degree of differentiation. These criteria include histology of the original tumor, histology of xenografts, in vitro morphology, and carcinoembryonic antigen expression. On this basis, the cell lines used were either moderately well or poorly differentiated. The poorly differentiated cell lines adhered to surfaces coated with laminin or reconstituted basement membrane extract (Matrigel) to a significantly greater extent than the moderately well differentiated lines with the exception of one moderately well differentiated line that was derived from a highly aggressive signet ring cell carcinoma. In addition, the poorly differentiated cell lines exhibited considerable spreading on laminin and Matrigel after adherence that was not evident for the moderately well differentiated lines. The adherence of these cell lines on fibronectin-coated surfaces did not correlate as well with differentiation although, in general, poorly differentiated cell lines adhered better than moderately well differentiated lines. None of the cells that adhered to fibronectin exhibited the extensive spreading seen on laminin. The specificity of tumor cell interactions with extracellular matrix glycoproteins was examined using synthetic peptides which correspond to sequences within these proteins that are recognized by cell surface receptors. The pentapeptide YIGSR-NH2 significantly inhibited the adherence and spreading of the tumor cell lines on laminin, but not on fibronectin. The peptide RGDS, however, did not inhibit tumor cell interactions with laminin although it did inhibit their interactions with fibronectin. Thus, the interactions of colon carcinoma cells with laminin and fibronectin are probably mediated by separate receptors. Taken together, the data demonstrate that cells derived from colon carcinomas exhibit considerable variation in their ability to interact with extracellular matrix components, and that this variability is related to the degree of differentiation of original tumor.