Experiments were carried out aboard COSMOS 2044 to determine the effects of spaceflight on immunologically important cell function and distribution. Control groups included vivarium, synchronous, and antiorthostatically suspended rats. In one experiment, rat bone marrow cells were examined in Moscow, for their response to recombinant murine granulocyte/monocyte colony-stimulating factor (GM-CSF). In another experiment, rat spleen and bone marrow cells were stained in Moscow with a variety of antibodies directed against cell surface antigenic markers. These cells were preserved and shipped to the United States for analysis on a flow cytometer. Bone marrow cells from flown and suspended rats showed a decreased response to granulocyte/monocyte colony-stimulating factor compared with bone marrow cells from control rats. Of the spleen cell subpopulations examined from flown rats, only those cells expressing markers for suppressor-cytotoxic T- and helper T-cells showed an increased percentage of stained cells. Bone marrow cells showed an increase in the percentage of cells expressing markers for helper T-cells in the myelogenous population and increased percentages of anti-asialo granulocyte/monocyte-1-bearing interleukin-2 receptor-bearing pan T- and helper T-cells in the lymphocytic population. Cell populations from rats suspended antiorthostatically did not follow the same pattern of distribution of leukocytes as cell populations for flown rats. The results from COSMOS 2044 are similar, but not identical, to earlier results from COSMOS 1887 and confirm that spaceflight can have profound effects on immune system components and activities.

Studies of peripheral blood lymphocytes from astronauts indicate that microgravity depresses T-cell responsiveness. However, this effect has not been examined in cells of peripheral lymphatic tissue, where most lymphocytes are located. In this study, inguinal lymph node lymphocytes from rats flown on the COSMOS 2044 mission were tested for proliferation and interleukin-2 (IL-2) production. Cells cultured with mitogenic lectins, phorbol ester, and calcium ionophore, or T-cell mitogen and lymphokine, were assayed for DNA synthesis by [3H]thymidine incorporation. Lymphocytes incubated with a T-cell mitogen alone also were tested for IL-2 production. Proliferation of lymphocytes from flight rats was not significantly different from controls for any of the mitogens tested. Furthermore, lymph node lymphocytes from flight rats was not significantly different from controls for any of the mitogens tested. Furthermore, lymph node lymphocytes from control and flown rats produced similar amounts of IL-2. Thus microgravity may act on lymphocytes in a tissue-specific manner, a new finding that could impact on the evaluation of spaceflight effects on immunocompetence.

How animals respond to a changing environment is a key question in ecological research. Animals living at higher latitudes are exposed to pronounced seasonal differences in both climate and in resource availability. Endotherms living in those environments have the ability to maintain a constant high body temperature (T b), over a wide range of ambient temperatures (T a). Nonetheless, many endotherms display seasonal shifts in metabolic rate (MR). Here, we studied the annual and circadian cycle of T b and heart rate (HR) in female moose (Alces alces) in relation to activity and T a. HR also can be used as a proxy of MR to calculate energy budgets. We deployed biologgers to 12 free-ranging female moose; a temperature sensor in the rumen, a HR logger subcutaneously, and a GPS collar equipped with acceleration and T a sensors. We documented seasonal differences in T b , HR and activity of moose, with lower levels during winter and higher values during summer. The highest daily mean T b and HR were 38.64 • C (10 July) and 71.9 beats per minute (bpm; 26 June), whereas the lowest daily mean T b and HR were 38.03 • C (17 March) and 40.5 bpm (6 March). High-resolution T b and activity data allowed us to detect circadian and ultradian rhythmicity throughout the year. Based on previous calibration studies, MR decreased by 60% from the highest to the lowest point. Our results demonstrate hypometabolism including lower T b and HR during winter as a strategy to reduce energy expenditure during periods with colder climate and limited availability of resources.

Researchers around the world capture bears of many species in their winter dens for a variety of purposes. Here, we found that brown bears had an arousal as a result of the captures and their hibernation was disrupted for several weeks.

Degenerative joint diseases caused by rheumatism, joint dysplasia or traumata are particularly widespread in countries with high life expectation. Although there is no absolutely convincing cure available so far, hyaline cartilage and bone defects resulting from joint destruction can be treated today by appropriate transplantations. Recently, procedures were developed based on autologous chondrocytes from intact joint areas. The chondrocytes are expanded in cell culture and subsequently transplanted into the defect areas of the affected joints. However, these autologous chondrocytes are characterized by low expansion capacity and the synthesis of extracellular matrix of poor functionality and quality. An alternative approach is the use of adult mesenchymal stem cells (MSCs). These cells effectively expand in 2D culture and have the potential to differentiate into various cell types, including chondrocytes. Furthermore, they have the ability to synthesize extracellular matrix with properties mimicking closely the healthy hyaline joint cartilage. Beside a more general survey of the architecture of hyaline cartilage, its composition and the pathological processes of joint diseases, we will describe here which advances were achieved recently regarding the development of closed, aseptic bioreactors for the production of autologous grafts for cartilage regeneration based on MSCs. Additionally, a novel mathematical model will be presented that supports the understanding of the growth and differentiation of MSCs. It will be particularly emphasized that such models are helpful to explain the well-known fact that MSCs exhibit improved growth properties under reduced oxygen pressure and limited supply with nutrients. Finally, it will be comprehensively shown how different analytical methods can be used to characterize MSCs on different levels. Besides discussing methods for non-invasive monitoring and tracking of the cells and the determination of their elastic properties, mass spectrometric methods to evaluate the lipid compositions of cells will be highlighted.