Adherence and regulation of leukotaxis

PMNs upon stimulation by a chemoattractant adhere to a substratum and then in amoeboid fashion migrate toward the source of the attractant. We have studied molecular events in both adherence and migration and have arrived at the following conclusions: 1) PMNs, like other motile cells such as highly metastatic tumor cells, can use laminin to attach to Type IV basement membrane collagen. PMNs may use this anchoring mechanism in their emigration from the vasculature. 2) Attached cells may be stimulated to migrate as a result of the chemo-attractant-induced inactivation of lipomodulin, a natural inhibitor of phospholipase A2, an enzyme that may be essential for chemotaxis. 3) The substrate for this enzyme is generated by both the CDP-choline and transmethylation pathways. These pathways may be regulated by another enzyme, transglutaminase (TGase). 4) Natural substrates of TGase, such as uteroglobin, inhibit leukocyte chemotaxis, again suggesting a regulatory role for TGase in chemotaxis. 5) Tumor cells also produce inhibitors of chemotaxis. In addition to protecting the tumor from the host's phagocytes, these inhibitors may be related to normal modulators of cell motility. Therefore, determination of their mode of action could increase our understanding of this type of cell behavior.

The Goodpasture-like syndrome in mice induced by intravenous injections of anti-type IV collagen and anti-laminin antibody

Laminin and Type IV collagen are both components of basement membrane. Antibodies to these two proteins, when injected into mice, were found to accumulate in all basement membranes examined, but at highest levels in kidney, liver, and spleen. An acute respiratory distress syndrome was noted shortly after injection. A transient segmental proliferative glomerulonephritis was observed both in the heterologous (early) and autologous (late) phase. The glomerular basement membrane of mice injected with anti-Type IV collagen antibodies was observed to be thickened and to contain dense deposits in the lamina rara externa and lamina rara interna.

Adhesion characteristics of murine metastatic and nonmetastatic tumor cells in vitro

We have studied the attachment of mouse fibroblasts, transformed nonmetastatic fibroblasts, and metastatic fibrosarcoma cells to various substrates. The metastatic cells attach preferentially to type IV (basement membrane) collagen in the absence of serum, compared to type I collagen and plastic. In the presence of fibronectin, these cells attach well to both type I and type IV collagens. The normal and transformed fibroblasts attach to all these substrates, although the transformed fibroblasts attach more slowly. The ability to attach to type I collagen and plastic is correlated with the levels of fibronectin and collagen produced by these cells. The data indicate that the transformed and metastatic cells differ from normal cells in their attachment properties and ability to synthesize matrix proteins. The metastatic cells possess a unique system for binding to type IV collagen that could be important in enabling these cells to penetrate tissues bounded by basement membranes.

Identification of functional tumor vessels by resorcin-crystal violet stain infusion

A resorcin-crystal violet solution of low viscosity injected into the circulatory plexus supplying a tumor is used to identify and characterize functional tumor vessels. Unstained sections of tumor tissue demonstrate heavily stained vascular endothelium with no leakage of stain to extravascular tissue for intact vessels, and little or no background staining. The method is simple to apply for tumor vessel morphology and morphometry.

Elastic behavior of postmortem human lungs: effects of aging and mild emphysema

The elastic behavior of postmortem human lungs has been studied in an effort to differentiate the effects of normal aging from those of mild emphysema. Static pressure-volume (P-V) curves were measured in 50 lungs obtained from men 15-85 yr of age, including 12 lungs with mild-to-moderate emphysema. The emphysema was quantitatively assessed by gross and microscopic methods. The P-V relationship in all lungs is accurately described by the empirically fitted equation, P = alpha1ea2v. This expression is useful because the two parameters separate the effects of elastic behavior (alpha1) from size (alpha2) on the P-V curve. There is a close negative correlation (R = -0.94) Between age and alpha1 in normal lungs but no significant age dependence of alpha2. Further decreases in alpha1 are found in most emphysematous lungs. Alpha1 is more than 2 SEE below the age-predicted mean in five of nine lungs with minimal emphysema (1-10% by point count) and more than 5 SEE below the mean in the three more severely affected lungs. There is a close correlation (R = +0.90) between alpha1 and the alveolar surface-to-volume ratio in both normal and emphysematous lungs.