The expression pattern and inhibitory influence of Tenascin-C on the growth of spiral ganglion neurons suggest a regulatory role as boundary formation molecule in the postnatal mouse inner ear.

Sensorineural hearing loss, as a consequence of acoustic trauma, aging, genetic defects or ototoxic drugs, is highly associated with irreversible damage of cochlear hair cells (HCs) and secondary degeneration of spiral ganglion (SG) cells. Cochlear implants (CIs), which bypass the lost HC function by direct electrical stimulation of the remaining auditory neurons, offer an effective therapy option. Several studies imply that components of the extracellular matrix (ECM) have a great impact on the adhesion and growth of spiral ganglion neurons (SGNs) during development. Based on these findings, ECM proteins might act as bioactive CI substrates to optimize the electrode-nerve interface and to improve efficacy of these implants. In the present study, we focused on the ECM glycoproteins Tenascin-C (TN-C), Laminin (LN), and Fibronectin (FN), which show a prominent expression along the growth route of SGNs and the niche around HCs during murine postnatal development in vivo. We compared their influence on adhesion, neurite length, and neurite number of SGNs in vitro. Moreover, we studied the expression of the chondroitin sulfate proteoglycan (CSPG) dermatan sulfate-dependent proteoglycan-1 (DSD-1-PG), an interaction partner of TN-C. In sum, our in vitro data suggest that TN-C acts as an anti-adhesive and inhibitory factor for the growth of SGNs. The DSD-1 carbohydrate epitope is specifically localized to HC stereocilia and SG fibers. Interestingly, TN-C and the DSD-1-PG exhibit a mutually exclusive expression pattern, with the exception of a very restricted region beneath the habenula perforata, where SG neurites grow through the basilar membrane (BM) toward the HCs. The complementary expression of TN-C, LN, FN, and the DSD-1 epitope suggests that TN-C may act as an important boundary formation molecule in the developing postnatal mouse inner ear, which makes it a promising candidate to regulate neurite outgrowth in the light of CIs.

Warming experiments underpredict plant phenological responses to climate change.

Warming experiments are increasingly relied on to estimate plant responses to global climate change. For experiments to provide meaningful predictions of future responses, they should reflect the empirical record of responses to temperature variability and recent warming, including advances in the timing of flowering and leafing. We compared phenology (the timing of recurring life history events) in observational studies and warming experiments spanning four continents and 1,634 plant species using a common measure of temperature sensitivity (change in days per degree Celsius). We show that warming experiments underpredict advances in the timing of flowering and leafing by 8.5-fold and 4.0-fold, respectively, compared with long-term observations. For species that were common to both study types, the experimental results did not match the observational data in sign or magnitude. The observational data also showed that species that flower earliest in the spring have the highest temperature sensitivities, but this trend was not reflected in the experimental data. These significant mismatches seem to be unrelated to the study length or to the degree of manipulated warming in experiments. The discrepancy between experiments and observations, however, could arise from complex interactions among multiple drivers in the observational data, or it could arise from remediable artefacts in the experiments that result in lower irradiance and drier soils, thus dampening the phenological responses to manipulated warming. Our results introduce uncertainty into ecosystem models that are informed solely by experiments and suggest that responses to climate change that are predicted using such models should be re-evaluated.

Psychological testing/trait and group dynamics during 110-day in an isolated environment.

Studies about the influence and differences of cultural and personal traits will become important for the increasing number of short-duration space flights of international crews supporting the International Space Station (ISS) and for long duration flights of international crews on ISS. The objective of this project was to investigate personal changes during 110-day isolation in the Russian Experiment Module. The Giessen Test (GT) was used to determine if personal traits of the subjects change during isolation. The GT was chosen as an individual diagnostic instrument because it includes an important range of social views and reactions. The GT reveals which characteristics a person, in this case a crew member, ascribes about him/herself (personal-picture). Questions about personal qualities were asked indirectly to better reveal psychosocial tendencies and defense mechanisms. Many personality tests focus on deriving information about how the subject "really" is. However, the GT deviates from this pure individual psychological ideal test construction and focuses on how the subject represents him/herself in psychoanalytically relevant categories in group relationships. We hypothesized that personal traits become more explicit and accentuated during prolonged confinement. Accentuations of personal traits were predicted due to the experience on MIR station where the American astronauts realized how different their Russian colleagues become compared to their common training time on the ground. The formation of subgroups was predicted, as it is often observed within different types of groups in Japanese, Russian isolation studies and at the Japanese Antarctic research station, Syowa.

Subjective exercise load index and motivation during long-duration confinement.

The objectives of this project were to investigate exercise load index and motivation related to long-duration confinement in the hermetic chamber.

Changes of catecholamine excretion during long-duration confinement.

Simulation studies have become the main source of data about small group interactions during prolonged isolation, from which it should be possible to anticipate crew problems during actual space missions. International Space Station (ISS) astronauts and cosmonauts will form one international crew, although living in different national modules. They will have joint flight protocols, and at the same time, fulfill a number of different tasks in accord with their national flight programs. Consistent with these concepts, we studied two simultaneously functioning groups in a simulation of ISS flight. The objective of this study was to investigate physiological parameters (such as catecholamine excretions) related to long-duration confinement in the hermetic chamber, simulating International Space Station flight conditions. We also planned to evaluate the relationship between epinephrine/norepinephrine with group dynamics and social events to predict unfavorable changes in health and work capability of the subjects related to psychological interaction in the isolation chamber.

[Surgical outcome of single segment ventral fusion with plate osteosynthesis in therapy refractory chronic cervico-brachialgia]. / Operative Ergebnisse der monosegmentalen ventralen Fusion mit Plattenosteosynthese bei der therapieresistenten chronischen Zervikobrachialgie.

INTRODUCTION: In anterior cervical stabilization, collapses of the grafted bone with resulting localized kyphosis and graft dislocation has been reported. It was the aim of this clinical trial to evaluate the benefit of additional plating while taking specific implant-related complications into account. METHODS: The results of single level anterior cervical spinal fusion were evaluated. In 44 patients suffering from chronic cervical radicular pain with degenerative changes, arthrodesis with iliac-crest bone and plate fixation was performed. Apart from clinical parameters, the pre- and postoperative segmental kyphosis and cervical lordosis were evaluated. RESULTS: The total cervical alignment increased from 15.4 degrees to 18.5 degrees while the alignment of the fused segment increased from 2.6 degrees to 7.7 degrees. Postoperative decrease of correction did not occur. Bony fusion was confirmed in 95% after 12 months and 100% aller 36 months. Our results show that patients had more relief from radicular pain (80%) than from unspecific neck pain (66%). DISCUSSION: In single level anterior cervical fusion, additional plating successfully prevents dislocation of the bone graft and postoperative kyphosis. The clinical results and pseudarthrosis rate do not differ from studies without plating. Long. term follow-up studies are necessary to show the benefit of the reduced postoperative kyphosis.

Regulation of human renal adenocarcinoma cell growth by retinoic acid and its interactions with epidermal growth factor.

Retinoic acid (RA) is a natural derivative of vitamin A which regulates the growth and differentiation of epithelia. We have previously proposed that RA participates in compensatory kidney growth and reported that RA inhibits rat mesangial cell growth. This paper describes the effects of RA on a human renal adenocarcinoma cell line (PAD) under different growth conditions, and its interactions with epidermal growth factor (EGF). PAD cells were shown to express RA receptors alpha and beta by Northern blot analysis. In serum free cultures, addition of RA (10(-7) M) markedly increased thymidine incorporation by PAD cells (155 +/- 7% mean +/- SE vs. control in 6 separate experiments; P < 0.0001). RA also caused a significant increase in thymidine incorporation by PAD cells under conditions of rapid growth in serum supplemented medium (115 +/- 2% vs. control; P < 0.001). RA by itself was unable to reverse contact inhibition of PAD cell growth (NS vs. control), but it synergistically enhanced the mitogenic effect of EGF on confluent monolayers (110 +/- 0.6% vs. EGF alone; P < 0.05). Northern blot analysis demonstrated that PAD cells express EGF receptor mRNA, and this was not significantly modified by the addition of RA. Growth arrested (serum starved) PAD cells expressed RAR-alpha mRNA which was upregulated eightfold at three hours following the addition of 10% FCS. Thus, our data show that RA is directly mitogenic for serum starved human renal adenocarcinoma cells and that it exerts complex modulation of cell growth in the presence of EGF and serum components.

Interferon-gamma stimulates the secretion of IL-1, but not of IL-6, by glomerular mesangial cells.

IL-1 activity in culture supernatant and cell lysate from rat mesangial cells stimulated with interferon-gamma (IFN-gamma) was measured by a thymocyte proliferation assay. While IFN-gamma alone had no effect on the secretion or the intracellular pool of IL-1, the enhancement by IFN-gamma of IL-1 secretion in response to lipopolysaccharide (LPS) was observed. The stimulatory effect of culture supernatant on thymocyte proliferation was abrogated by preincubation with the anti-IL-1 antibody. At least 4-h incubation with IFN-gamma and LPS was required to detect enhancing effect of IFN-gamma. The addition of as little as 1 U/ml IFN-gamma significantly increased IL-1 secretion in the presence of 10 micrograms/ml LPS. The IL-6 activity in culture supernatants was determined by measurement of thymidine uptake in mouse IL-6-dependent cell line (MH60.BSF2). Mesangial cells secreted IL-6 in culture supernatant without additional stimuli and LPS distinctly increased it as described previously. However, in contrast to IL-1 production, no effect of IFN-gamma on IL-6 secretion was observed in the presence or absence of LPS. Moreover, we determined whether enhanced IL-1 release is associated with Ia expression on mesangial cells. IFN-gamma alone and the combination with LPS induced marked expression of Ia antigen, whereas LPS alone did not. We conclude that IFN-gamma stimulates the production of IL-1, but not IL-6, by mesangial cells and suggest an important role of IFN-gamma in the pathogenesis of glomerulonephritis by regulating the mesangial production of IL-1 and the accessory cell function of mesangial cells.

Rapid induction of intercellular adhesion molecule-1 on monocytes and myelomonocytic cell lines after interferon gamma treatment.

The ICAM-1 molecule is an important adhesion factor that facilitates lymphocyte activation as well as the movement of lymphocytes into solid tissues. It is poorly expressed on circulating monocytes but higher levels have been described following the use of some activation factors. While previous work has emphasized the role of interferon gamma in inducing increased ICAM-1 expression on nonleukocytic cells, we have demonstrated time- and dose-dependent increases on human monocytes and two myelomonocytic cell lines (Rc2A & U937). The increased level of ICAM-1 expression on the Rc2A cells was associated with higher accessory cell activity as determined by an increased mitogen and allogeneic response but specific antibody inhibition studies indicated only a partial dependence (up to 50%) on this molecule. Class II MHC expression and IL-1 production were not elevated by IFNg treatment of these cells, indicating that other factors account for the remainder of the incremental activity observed following this treatment.

Epidermal growth factor and transforming growth factor alpha stimulate or inhibit proliferation of a human renal adenocarcinoma cell line depending on cell status: differentiation of the two pathways by G protein involvement.

Transforming growth factor alpha production by renal tumors, acting through the epidermal growth factor receptor, has been implicated in malignant transformation by studies which compared gene expression in neoplastic and normal human tissue. We sought confirmation of this hypothesis by measuring the growth responses of a human renal tumor cell line to the addition of epidermal growth factor and transforming growth factor alpha. Surprisingly, it was found that both growth factors could induce either mitogenic or inhibitory signals depending on the growth status of the cultures. Confluent cultures were stimulated by both growth factors, and nonconfluent cultures were inhibited, as determined by thymidine incorporation, cell cycle analysis, and direct cell counting. These signals appear to use different transduction pathways, as growth factor induced inhibition was reversed by Bordetella pertussis toxin (which affects G protein signaling), whereas the stimulatory effects were not reversed. Two clones isolated from these cells responded in the same manner as the main cell isolate. These data show that the same cell may display opposite responses to equivalent concentrations of the same growth factor, depending on the transduction pathway used after triggering by receptor occupancy of either ligand (epidermal growth factor or transforming growth factor alpha).

Differential control of mesangial cell proliferation by interferon-gamma.

Rat mesangial cells were shown to be sensitive to recombinant interferon-gamma (IFN-gamma). IFN-gamma reduced thymidine uptake by these cells and inhibited cell proliferation. Incubation of the cells with 1000 U/ml IFN-gamma decreased thymidine uptake by up to 64% and cell numbers were decreased by 17%. The effects of IFN-gamma were dose and time dependent and were partially reversible by the anti-IFN-gamma monoclonal antibody DB-1. This lymphokine did not reduce incorporation of RNA and protein precursors however. Measurements of 3H-uridine and 3H-leucine incorporation indicated significant increases in RNA and protein synthesis (37% and 45%, respectively) on a per cell basis. The mitogenic effects of IL-1 and platelet-derived growth factor (PDGF) were also susceptible to IFN-gamma-mediated inhibition but the mitogenic response to epidermal growth factor (EGF) was much less sensitive. We conclude that while IFN-gamma may act to modulate the mitogenic signals provided by some factors such as IL-1 and PDGF, the response to EGF appears to be unaffected.

T-lymphocyte response to cytokines in B-chronic lymphocytic leukemia.

The mechanisms underlying abnormal T-cell function in B-chronic lymphocytic leukemia (B-CLL) are unknown. We have studied B-CLL T-cell activation pathways in the rigorous absence of leukemic cells and with controlled numbers of accessory cells present. The responsiveness to added recombinant IL-1 and IL-2 was assessed. We have found that under optimal culture conditions B-CLL T cells had a normal PHA-induced proliferative response in terms of incorporated 3H-thymidine per T cell. Also the capacity of mitomycin-C treated B-CLL monocytes to support autologous T-cell mitogenesis was normal. However, a subtle difference between normal and B-CLL T cells emerged with respect to cytokine responsiveness. While the PHA response of purified normal T cells in the absence of monocytes was augmented by rIL-1, this could not be demonstrated for B-CLL T cells. A much greater degree of augmentation occurred with added rIL-2 in the case of both normal and B-CLL T cells. In the presence of 20% autologous monocytes rIL-1 and rIL-2 had no effect on mitogenesis. We conclude that B-CLL T cells have an abnormal profile of cytokine responsiveness which is consistent with observed abnormalities of subset distribution, and which may contribute to the clinical immunodeficiency in B-CLL.

T cells and CD45R expression in B-chronic lymphocytic leukemia.

A major secondary immunodeficiency exists in B cell derived chronic lymphocytic leukemia (B-CLL) which involves both humoral and cellular immunity and is largely unexplained. Several T cell subset redistributions have been noted in B-CLL. We therefore examined in more detail the immunophenotype of T cells by assessing CD45R expression using a two-colour immunofluorescence technique. The proportion of CD45R+ cells among CD3+, CD4+ and CD8+ cells in B-CLL was significantly (p less than 0.001) higher than in corresponding normal cell populations. We also sought relationships between major T cell subsets and progress of disease and found strongly positive correlations between the total leukocyte count in B-CLL and numbers of CD3+, CD4+, CD8+ cells and monocytes. Further, in patients with clinically more advanced disease, CD3+ and CD4+ cells were present in higher numbers than in patients with less advanced disease (p less than 0.05). CD8+ cells, CD4/CD8 ratio, monocytes and total leukocyte count were not significantly different when comparing the less advanced and more advanced disease patients. An excess of CD45R+ suppressor-inducer T cells has implications for both B and T cell dysfunction and for disease progression.

Retinoic acid affects the cell cycle and increases total protein content in epithelial cells.

Retinoids and particularly retinoic acid (RA) have been incriminated in the adaptation to uninephrectomy and compensatory kidney growth in humans. However, there is no data assessing the effects of RA on renal cells. Since the bulk of the compensatory kidney growth is due to tubular cells, we studied the effects of RA, retinol and epidermal growth factor (EGF) on a rabbit kidney epithelial cell line RK13 in culture. RA significantly increased thymidine incorporation by 42 +/- 8% (P less than 0.01). This increase appeared as soon as three hours after adding RA and could still be observed after five days. Total protein content was also increased by RA by 37 +/- 4% (P less than 0.01). Flow cytometer analysis showed a significant decrease in the percentage of resting cells (G0-G1 phases) induced by RA (-9.4 +/- 2%; P less than 0.01). We observed similar results in growth factor free medium, and the RA induced changes were the same in confluent and non-confluent cells. Retinol did not modify thymidine incorporation or total protein content. EGF increased by 75% thymidine incorporation (P less than 0.01). In serum free conditions RA failed to have a synergistic effect with EGF. These data show that RA is able to induce modifications in kidney epithelial cells compatible with those observed in hypertrophy while retinol is not. These modifications are not due to other growth factor potentiation but to RA itself, and are independent of the contact-inhibition phenomenon.

Phenotypic definition of primed T cells in human renal allografts. Use of the CD45R marker.

Immunohistological studies indicate that T cells and macrophages are the major components of human kidney allograft infiltrates. Recent work has demonstrated a division of T lymphocytes into 2 subpopulations with distinct functions on the basis of their expression of the CD45R antigen (CD45R+ "naive" and CD45R- "memory" T cells). This study analyzes CD45R expression on circulating T cells and T cells infiltrating renal allografts in patients undergoing rejection and/or cyclosporine nephrotoxicity. The percentage of circulating T cells that expressed CD45R in patients with rejecting (63 +/- 4) or stable grafts (66 +/- 3) was not different from values obtained for normal donors (62 +/- 3). In contrast, the percentage of T cells expressing CD45R infiltrating rejecting grafts was 21 +/- 2 and was not affected by the stage of rejection; in patients with CsA toxicity the value was 22 +/- 6. The reduced proportion of T cells that expressed CD45R in the allograft may reflect a change in status from the naive state due to alloantigenic stimulation (which can be demonstrated in vitro) and/or a propensity of memory T cells to enter or be retained in an allograft.