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Rewetting can strongly affect the matter balance of peatlands. Owing to evidence of increasing CH emissions and P mobilisation after rewetting, the effects of peatland restoration on climate, eutrophication risks and related controversies are discussed. Our study focuses on the role of helophytes in the carbon and nutrient balance of rewetted fen grasslands of NE Germany. We hypothesise that the helophytes Carex riparia, Glyceria maxima, Phalaris arundinacea, Phragmites australis and Typha latifolia differ in biomass production and nutrient standing stock according to site conditions and harvest time. We analysed the helophyte biomass three times a year and continuously measured water levels and quality. Biomass production, nutrient standing stock and litter accumulation were highly species specific and depended on nutrient availability, mean water levels and harvesting time. We conclude that helophytes store considerable amounts of carbon and temporarily improve the water quality by withdrawing high amounts of nutrients from the top soil during the growing season, and by reducing nutrient discharges. Restoring peatlands as effective nutrient and carbon sinks in the landscape should favour highly productive potentially peat-forming helophytes as Phragmites australis by establishing adequate water levels. If nutrients are to be removed from the degraded peatland, then management can combine the restoration of helophyte stands by rewetting with harvesting measures. [ABSTRACT FROM AUTHOR]

The objective of the present study was to evaluate the cellular effects of the oncolytic HSV-1 based vector, G207, on the tumor microenvironment. We established progressively growing intracerebral xenografts in athymic nude rats generated from three different human GBM surgical specimens. The lesions were identified by MRI and subsequently injected with a concentrated vector stock. The animals were killed 10 or 30 days after G207 injection and the tumors were quantitatively evaluated for virus-induced changes in proliferation, apoptosis and vascularity. Moreover, we assessed vector spread as well as the infiltration pattern of CD68-positive inflammatory cells. In all G207-injected lesions, immunostaining identified widespread regions of viral infection and replication (plaques). Proliferation indices were significantly lower, whereas apoptotic counts were significantly elevated in plaques as compared with that in non-infected areas of the same lesions, as well as in corresponding control xenografts. Furthermore, there was a significant decline in the number of blood vessels in the plaques and the vascular area fractions were reduced. CD68-positive inflammatory cells accumulated in the plaques. The present study highlights the favorable cellular responses to G207 treatment seen from a clinical viewpoint, such as reduced tumor cell proliferation, more frequent events of tumor cell death and a strongly attenuated tumor vascular compartment. However, our results suggest that transduction of a significant volume of tumor tissue is essential, as these beneficial changes were only observed in areas of active viral replication, leaving non-transduced tumor tissues unaffected. [ABSTRACT FROM AUTHOR]

Tumor cells, including renal cell carcinoma (RCC) cells, do not effectively stimulate T lymphocyte responses against specific antigens presented on their surface. Reasons for this low immunogenicity may include low or absent expression of MHC class I and/or class II molecules, as well as accessory and costimulatory molecules. We used tumor cell pretreatment with cytokines, together with monoclonal antibodies (mAbs) directed at receptors for costimulatory molecules, to render RCC cells immunostimulatory. Interferon-γ or tumor necrosis factor-α pretreatment enhanced expression of MHC class I and class II molecules, as well as CD54, but had only minimal effects on T cell activation. A CD28 mAb, or an even more effective combination of CD28 and CD5 mAb, induced strong primary proliferative responses of allogeneic resting T lymphocytes. Cytokine pretreatment further augmented this T cell response in vitro and allowed T cell expansion and establishment of T cell lines. Stimulation of T cells with autologous RCC cells resulted in a similar T cell activation but with the expansion of cytolytic T cells directed at autologous MHC class II molecules. These experiments demonstrate that cytokines combined with costimulatory mAbs are useful for increasing the immunogenicity of tumor cells. They also indicate, however, that autologous MHC class II expression on tumor cells, together with strong costimulation, may lead to the activation of autoreactive T cells. [ABSTRACT FROM AUTHOR]