Measuring the Short‐term Success of Grassland Restoration: The Use of Habitat Affinity Indices in Ecological Restoration

Agricultural intensification threatens grasslands worldwide and the restoration of grasslands from arable lands can at least partially counter this threat. We studied grassland restoration by following early successional changes of arthropod assemblages (spiders, Araneae; true bugs, Heteroptera; orthopterans, Orthoptera; and ground beetles, Carabidae) on 1‐ and 2‐year‐old restorations using arable lands and native grasslands as two ends of the succession timescale. To examine the changes in species composition among the habitat types, we used habitat affinity indices based on fidelity and/or specificity of the species. We found that the number of species did not differ between habitat types, while species composition changed markedly with time. Species richness was thus not adequate to detect favorable changes after grassland restoration. Habitat affinity indices, on the other hand, were useful to detect compositional changes caused by the increasing numbers of species characteristic of target grasslands as early as the second year after restoration. Habitat affinity indices are easy‐to‐use, easy‐to‐interpret measures of restoration success; therefore, we recommend their use as measures complementary to species richness and simple similarity. Our results show that sowing low‐diversity seed mixture followed by mowing and grazing can be particularly successful in grassland restoration in time periods as short as 2 years.     

Activated human T lymphocytes express a functional C3a receptor

The C3a molecule is an anaphylatoxin of the C system with a wide spectrum of proinflammatory effects predominantly on cells of myeloid origin. In this study we investigated the expression of the high affinity receptor for C3a (C3aR) in human T lymphocytes using receptor-specific mAb. C3aR expression was detected in CD4(+) and CD8(+) blood- or skin-derived T cell clones (TCC) from birch pollen-sensitized patients with atopic dermatitis. No significant difference in C3aR expression in CD4(+) or CD8(+) TCCs could be observed. In contrast to C3a(desArg), C3a led to a transient calcium flux in TCCs expressing the C3aR, whereas C3aR-negative TCCs were unreactive. Circulating T cells from patients suffering from severe inflammatory skin diseases expressed the C3aR, whereas no expression of C3aR could be found in unstimulated T lymphocytes from patients with mild inflammatory skin diseases or from healthy individuals. Type I IFNs, which are potent stimulators of cellular immunity, were identified as up-regulators of C3aR expression in vitro in freshly isolated or cloned T lymphocytes. Moreover, C3aR(+) T cells were found at the sites of injection in IFN-beta-treated patients with multiple sclerosis. These data provide direct evidence for the expression of C3aR on activated human T lymphocytes; this may point to a biological function of C3a in T cell-dependent diseases.     

Experiences in the treatment of tumour of base of the tongue with high dose rate interstitial radiotherapy on the basis of a retrospective analysis

PURPOSE: To describe the role, the execution and the importance of interstitial radiotherapy in the irradiation of the base of tongue cancer. MATERIAL AND METHODS: Between January, 1993 and December, 1998 nineteen patients with primary squamous cell cancer of the base of tongue (1 T1N0, 3 T2N0, 2 T3N0, 2 T3N2, 3 T4N0, 6 T4N1, 2 T4N2) were managed with brachytherapy partly with definitive intention combined with teletherapy (60-66 Gy) as a boost, partly as a single postoperative treatment. Irradiation was carried out by HDR after-loading (Ir-192) unit, using rigid needle or flexible plastic catheter. The treatment plan was made by PLATO 3D brachytherapy planning system. In case of boost the mean total dose of brachyherapy was 22 Gy (12-30 Gy), in postoperative treatment it was 27 Gy (24-30 Gy). RESULTS: 6-8 weeks after the definitive radiotherapy the CT/MR showed complete remission in 67% and partial remission in 33% of the patients. Of all treated patients during the mean follow-up period (30 months) the local tumour control was 42%. Five patients (26%) died in local failure. Six patients (32%) are alive with tumour. Osteoradionecrosis and fistula did not occur. CONCLUSIONS: In the oncological treatment of the advanced base of tongue tumour the combination of percutan and interstitial radiotherapy seems to be very advantageous,because it improves not only the curability, but the patients' quality of life as well.     

Cutting edge: Cbl-b: one of the key molecules tuning CD28- and CTLA-4-mediated T cell costimulation

Cbl-b negatively regulates CD28-dependent T cell activation. In this report, we tested the hypothesis that CD28 and CTLA-4 have opposite roles in tuning T cell activation threshold by controlling the levels of Cbl-b protein expression. We demonstrate that CD28 costimulation potentiates TCR-induced Cbl-b degradation, whereas CTLA-4-B7 interaction is required for Cbl-b re-expression. In support of this finding, Cbl-b expression in CTLA-4 knockout (KO) T cells is significantly reduced, and treating CTLA-4KO mice with human CTLA-4Ig to block CD28-B7 interaction restores Cbl-b expression on T cells. Furthermore, CD28 and CTLA-4 costimulatory effects are compromised in Cbl-bKO T cells. These observations indicate that CD28 and CTLA-4 tightly regulate Cbl-b expression which is critical for establishing the threshold for T cell activation.     

Spontaneous renal allograft acceptance associated with "regulatory" dendritic cells and IDO

MHC-mismatched DBA/2 renal allografts are spontaneously accepted by C57BL/6 mice by poorly understood mechanisms, but both immune regulation and graft acceptance develop without exogenous immune modulation. Previous studies have shown that this model of spontaneous renal allograft acceptance is associated with TGF-beta-dependent immune regulation, suggesting a role for T regulatory cells. The current study shows that TGF-beta immune regulation develops 30 days posttransplant, but is lost by 150 days posttransplant. Despite loss of detectable TGF-beta immune regulation, renal allografts continue to function normally for >200 days posttransplantation. Because of its recently described immunoregulatory capabilities, we studied IDO expression in this model, and found that intragraft IDO gene expression progressively increases over time, and that IDO in "regulatory" dendritic cells (RDC) may contribute to regulation associated with long-term maintenance of renal allografts. Immunohistochemistry evaluation confirms the presence of both Foxp3+ T cells and IDO+ DCs in accepted renal allografts, and localization of both cell types within accepted allografts suggests the possibility of synergistic involvement in allograft acceptance. Interestingly, at the time when RDCs become detectable in spleens of allograft acceptors, approximately 30% of these mice challenged with donor-matched skin allografts accept these skin grafts, demonstrating progression to "true" tolerance. Together, these data suggest that spontaneous renal allograft acceptance evolves through a series of transient mechanisms, beginning with TGF-beta and T regulatory cells, which together may stimulate development of more robust regulation associated with RDC and IDO.     

Synthesis and in vitro antitumoral activity of novel O,O'-di-2-alkyl-(S,S)-ethylenediamine-N,N'-di-2-propanoate ligands and corresponding platinum(II/IV) complexes

Syntheses of two novel ligand precursors O,O'-diisopropyl- (1a) and O,O'-diisobutyl-(S,S)-ethylenediamine-N,N'-di-2-propanoate dihydrochloride monohydrate (1b) and the corresponding dichloroplatinum(II) (2a and 2b) and tetrachloroplatinum(IV) complexes (3a and 3b) are described here. The substances were characterized by IR, (1)H and (13)C spectroscopy and elemental analysis. Crystal structures were determined for 1a and the corresponding platinum(IV) complex, 3a. In vitro antiproliferative activity was determined against tumor cell lines: human adenocarcinoma HeLa, human myelogenous leukemia K562, human malignant melanoma Fem-x, rested and stimulated normal immunocompetent cells (human peripheral blood mononuclear PBMC cells) using KBR test (Kenacid Blue Dye binding test). The IC(50)(microM) values for the most active compound 3a were: 30.48+/-2.54; 12.26+/-2.60; 13.68+/-3.22; 80.18+/-24.07 and 71.30+/-21.70, respectively.