Multiple Beads Research Articles

Three‐dimensional growth and differentiation of ovarian tumor cell line in high aspect rotating‐wall vessel: Morphologic and embryologic considerations

Cancer of the ovary is the leading cause of death from gynecologic malignancy. To understand better these aggressive tumors, the development of in vitro models to study human ovarian cancer is critical. However, the establishment of long-term cell lines has been difficult, due to the generalized poor survival of patient tumor cells grown in primary culture. Satisfactory culture systems for ovarian tumor cells have therefore been limited. To study cellular interactions involved in the growth and differentiation of these tumors, a cell line was established from a mixed müllerian tumor of the ovary. This cell line, designated LN1, was cultured on microcarrier beads in the high aspect rotating-wall vessel. The tumor cells grown in this vessel readily proliferated without a requirement for cocultivation with a supportive cell layer. Evaluation of cellular morphology by phase contrast light microscopy and scanning electron microscopy revealed the presence of three-dimensional multicellular aggregates consisting of multiple cell-coated beads bridged together, as well as scattered aggregates of LN1 cells proliferating as spheroids free in suspension. In contrast to conventional culture systems, culture in the high aspect rotating-wall vessel facilitated the generation of multiple cell types that could be recovered. These results illustrate the ability of this culture system to provide the biological conditions necessary for pluripotent cell growth.

Influence of acute pulmonary interstitial inflammation on kinetics of phagocytosis by alveolar macrophages.

The pulmonary alveolar macrophage (PAM) is central to lung cellular defenses and is a potential participant in lung injury, but little is known about the influence of the nature and anatomic pattern of acute lung injury on PAM function. To assess the relationship between ongoing pulmonary inflammation and PAM function, we evaluated PAM phagocytic kinetics in a model system of experimental interstitial adjuvant pneumonitis (EIAP) in calves. PAMs were obtained from lung one and seven days postinduction (dpi) of EIAP. Lesions were typical of EIAP, characterized by acute multifocal to coalescing exudative interstitial pneumonitis at 1 dpi, which progressed to granulomatous interstitial pneumonitis by 7 dpi. The total recoverable lung cells and percentage of neutrophils (PMNs) were elevated (P less than 0.01) from animals with EIAP at both 1 and 7 dpi, and there was a four-fold increase (P less than 0.01) in the PAM yield by 7 dpi. Linear regression equations revealed that a larger proportion of control PAMs were phagocytic than were PAMs from animals with EIAP. The mean initial phagocytic rates of PAM following acute lung injury were significantly elevated (P less than 0.05) over controls; this difference was concentration dependent and required a phagocytic bead stimulus concentration in excess of 12.5 x 10(6) beads/ml. PAMs from animals with EIAP had a greater maximum rate of phagocytosis (Vmax) and Km than control PAMs. PAMs from animals with EIAP had a slightly higher proportion of cells which phagocytosed multiple beads. Levels of beta-glucuronidase were elevated (P less than 0.02) in PAM from animals with EIAP at 7 dpi. The results document enhanced PAM phagocytic function in EIAP and differ from our previous experiments in which depressed PAM phagocytic indices were obtained in a model of virus-induced acute bronchiolitis and alveolitis. The functional activities of the PAMs thus appear to be modified by injury-specific events in the lung microenvironment which may, in part, reflect the nature and anatomic pattern of developing pulmonary inflammatory reactions.

Evidence for the phagocytic transport of intestinal particles in dogs and rats.

Fluorescent latex beads of two different colors were implanted into separate intestinal segments in individual dogs and rats. Mesenteric lymph node phagocytes subsequently contained multiple beads of one or the other color but rarely both colors, indicating that intestinal phagocytes transported the latex beads to the draining lymph node. Fluorescent labeled Escherichia coli was implanted into rat ligated intestinal segments, and rare mesenteric lymph node phagocytes subsequently contained fluorescent bacteria, suggesting that intestinal bacteria might be transported in the same manner as inert latex beads.

How to Minimize the Deformation Caused by Arc Welding

In the first section of this paper, the author describes several practical methods of minimizing the deformation caused by the application of arc welding on the hull construction, such as symmetrizing method, constraining method, water-cooling method, multiple beads method, heat-absorving method, and pre-straining method. And then, he explains the general matters on the carbon contents and the diameter of electrodes, the form of welding, the amount of electric current, and the speed of welding, to be taken care to minimize the deformation.