Humans subjected to periods of microgravity develop anemia, thrombocytopenia, and abnormalities in red blood cell structure. The causes of these abnormalities are complex and unclear. The in vitro effects of spaceflight on hematopoietic cell proliferation and differentiation were investigated during the space shuttle missions STS-63 (Discovery) and STS-69 (Endeavour). CD34+ bone marrow progenitor cells were cultured in liquid suspension culture and on hematopoietic supportive stromal cells using hollow-fiber culture modules. One set of cultures was maintained at microgravity (flight cultures) for the last 8-10 days of culture and a second control was at full gravity (ground control). Over the 11- to 13-test-day period, ground control culture total cell number increased 41.0- to 65.5-fold but flight culture total cell number increased only 10.1- to 17.6-fold (57-84% decrease). Comparing ground control cultures and microgravity cultures, respectively, for progenitor cell content, myeloid progenitor cell numbers expanded 2.6- to 17.5-fold compared with 0.9- to 7.0-fold and erythroid progenitor cell numbers expanded 2.0- to 4.1-fold in ground control cultures but actually declined at microgravity (>83% reduction). Moreover, microgravity cultures demonstrated accelerated maturation/differentiation toward the macrophage lineage. These data indicate that spaceflight has a direct effect on hematopoietic progenitor cell proliferation and differentiation and that specific aspects of in vitro hematopoiesis, particularly erythropoiesis, involve gravity-sensitive components.

Tom Cannon is Professor of Business Studies at Stirling University, Scotland, and Michael Willis is Management Research Fellow at Durham University Business School, England. This paper describes the results of a three year study of the issues, problems and opportunities faced by the smaller concern as it seeks to develop its exports. It has been argued that the propensity of small firms to be domestic market and service orientated runs counter to the needs of trading nations for companies able to build overseas business. The paper explores the evidence behind this and other nations, in particular whether it is true that small firms are inhibited from entering export markets and the patterns of overseas trading they follow. It also looks at whether there are any specific problems faced by small firms wanting to develop exports or international trade and what measures can be adopted to overcome these difficulties, either within the firm or by external policymakers.

A compact, flow-through oxygen sensor device based on luminescence quenching was used to monitor dissolved oxygen levels during mammalian cell growth on the STS-93 mission of the Columbia space shuttle. Excitation of an oxygen-sensitive ruthenium complex was provided by a radioluminescent light source (0.9 mm in diameter, 2.5 mm long), and the intensity of the resulting luminescence was measured by a simple photodiode detector. The use of radioluminescence for the excitation light source is a unique approach that provides many features important for long-term and remote monitoring applications. For the spaceflight experiment, human lung fibroblast cells (WI-38) were grown in hollow-fiber bioreactors. Oxygen concentration was measured in the flow path both before and after the bioreactor cartridge in order to gain information about the metabolism of the cells. The sensor was found to be nonperturbing to cell growth and withstood the challenging physical conditions of shuttle launch and landing while maintaining a stable calibration function. In addition, the sensor provided physically meaningful oxygen predictions.

Professor Tom Cannon is head of the Department of Business Studies at Stirling University and director of the Scottish Enterprise Foundation. This paper examines aspects of the ability of small firms to perform the type of role in industrial innovation often ascribed to them. All the firms in the study were in a constant process of adaption to their changing conditions and the corollary of these adaptations was innovation. Many innovations were not dramatic or major but the overall pace and scale was significant. In arriving at innovations relatively little use was made of external relationships, the sole exceptions being trading partners suppliers or buyers. The firms appeared to be highly adept at identifying internal innovations. The role adopted by the chief executive was critical in determining the nature of the organisational environment.

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