Effects of microgravity on osteoblast growth.

Studies from space flights over the past two decades have demonstrated that basic physiological changes occur in humans during space flight. These changes include cephalic fluid shifts, loss of fluid and electrolytes, loss of muscle mass, space motion sickness, anemia, reduced immune response, and loss of calcium and mineralized bone. The cause of most of these manifestations is not known and until recently, the general approach was to investigate general systemic changes, not basic cellular responses to microgravity.

Coordinate up-regulation of low-density lipoprotein receptor and cyclo-oxygenase-2 gene expression in human colorectal cells and in colorectal adenocarcinoma biopsies.

Many colorectal cancers have high levels of cyclo-oxygenase 2 (COX-2), an enzyme that metabolizes the essential fatty acids into prostaglandins. Since the low-density lipoprotein receptor (LDLr) is involved in the uptake of essential fatty acids, we studied the effect of LDL on growth and gene regulation in colorectal cancer cells. DiFi cells grown in lipoprotein-deficient sera (LPDS) grew more slowly than cells with LDL.

Osteoblast fibronectin mRNA, protein synthesis, and matrix are unchanged after exposure to microgravity.

The well-defined osteoblast line, MC3T3-E1 was used to examine fibronectin (FN) mRNA levels, protein synthesis, and extracellular FN matrix accumulation after growth activation in spaceflight. These osteoblasts produce FN extracellular matrix (ECM) known to regulate adhesion, differentiation, and function in adherent cells. Changes in bone ECM and osteoblast cell shape occur in spaceflight.

Significance of nodal uptake on indium 111 labeled leukocyte scans.

A retrospective study of 132 indium 111 labeled leukocyte scans on 129 patients was undertaken to determine the incidence and significance of activity in the neck, axilla, and groin suggestive of regional lymph nodes. Possible nodal uptake was observed in 35 out of 108 (32%) adults and 11 out of 21 (52%) children. Activity was characterized as symmetric or asymmetric.