Monocytes show immunoregulatory capacity on CD4+ T cells in a human in-vitro model of extracorporeal photopheresis.

Extracorporeal photopheresis (ECP) is a widely used immunomodulatory therapy for the treatment of various T cell-mediated disorders such as cutaneous T cell lymphoma (CTCL), graft-versus-host disease (GvHD) or systemic sclerosis. Although clinical benefits of ECP are already well described, the underlying mechanism of action of ECP is not yet fully understood. Knowledge on the fate of CD14+ monocytes in the context of ECP is particularly limited and controversial. Here, we investigated the immunoregulatory function of ECP treated monocytes on T cells in an in-vitro ECP model. We show that ECP-treated monocytes significantly induce proinflammatory T cell types in co-cultured T cells, while anti-inflammatory T cells remain unaffected. Furthermore, we found significantly reduced proliferation rates of T cells after co-culture with ECP-treated monocytes. Both changes in interleukin secretion and proliferation were dependent on cell-contact between monocytes and T cells. Interestingly, blocking interactions of programmed death ligand 1 (PD-L1) to programmed death 1 (PD-1) in the in-vitro model led to a significant recovery of T cell proliferation. These results set the base for further studies on the mechanism of ECP, especially the regulatory role of ECP-treated monocytes.

Inadequate environmental monitoring around offshore oil and gas platforms on the Grand Bank of Eastern Canada: are risks to marine birds known?

Petroleum exploration and production on the Grand Bank of eastern Canada overlaps with productive marine habitat that supports over 40 million marine birds annually. Environmental assessments for oil and gas projects in the region predict insignificant adverse effects on marine birds from oil spills, incineration in platform flares and collisions. Limited baseline data on seasonal occupancies and a failure to quantify the nature and extent of marine bird attraction to platforms and related mortality undermines these assessments. We conducted 22 surveys to offshore platforms on the Grand Bank during 1999-2003 to measure avian associations with platforms and to determine the level of monitoring needed to assess the risks to marine birds. We document seasonal shifts in marine bird occurrences and higher densities of auks (fall) and shearwaters (summer) around platforms relative to surrounding areas. The limited temporal and spatial coverage of our surveys is more robust than existing industry monitoring efforts, yet it is still inadequate to quantify the scale of marine bird associations with platforms or their associated mortality risks. Systematic observations by independent biologists on vessels and platforms are needed to generate reliable assessments of risks to marine birds. Instead, the regulatory body for offshore oil and gas in eastern Canada (Canada - Newfoundland and Labrador Offshore Petroleum Board; C-NLOPB) supports industry self-reporting as the accepted form of environmental monitoring. Conflicting responsibilities of oil and gas regulatory agencies for both energy development and environmental monitoring are major barriers to transparency, unbiased scientific inquiry and adequate environmental protection. Similar conflicts with the oil and gas regulatory body in the United States, the former Minerals and Management Service (MMS) were identified by the U.S. President as a major contributor to the Deepwater Horizon disaster in the Gulf of Mexico. The MMS has since been restructured into the Bureau of Ocean Energy Management, (BOEM) with separate departments responsible for drilling leases and the regulation of drilling activities. Similar restructuring of the oil and gas regulatory bodies in Canada is needed for better public information, scientific investigation and environmental protection in the offshore.

Lesional elastase activity in psoriasis, contact dermatitis, and atopic dermatitis.

Human leukocyte elastase (HLE) is a broad spectrum serine protease derived from neutrophils and macrophages. We developed an assay to determine HLE activity on the skin surface in patients with inflammatory skin diseases. HLE activity was absent in the skin of healthy controls. A massive increase of HLE activity was found in lesional skin of psoriasis (31 times), allergic contact dermatitis (55 times), and atopic dermatitis (35 times), but not in uninvolved skin of diseased patients. Therefore, this assay appears to represent a useful biochemical marker of epidermal inflammation. The presence of proteolytically active HLE in diseased epidermis, which is known to contain specific inhibitors of this enzyme, suggests a pathophysiologic role of this enzymatic activity in psoriasis, contact dermatitis, and atopic dermatitis.

Lesional elastase activity in psoriasis. Diagnostic and prognostic significance.

Human leukocyte elastase, a neutrophil-derived serine protease, is present in psoriatic lesions in an enzymatically active form. Our purpose was to assess the significance of human leukocyte elastase determinations in estimating the inflammatory activity of psoriatic lesions. A standardized method was used to analyse lesional elastase activity. Elastase activities were correlated with erythema, induration and hyperkeratosis of psoriatic lesions in 54 patients. Lesional elastase activities were also determined during treatment with salt-water bathing and UVB irradiation. Lesional elastase activity correlated with skin induration and was inversely correlated with hyperkeratosis of the lesions. Psoriatic lesions with high elastase activity responded well to therapy, whereas lesions with low elastase activity appeared to be comparatively resistant. This study shows that by quantitative determination lesional elastase activities it is possible to distinguish predominantly inflammatory from predominantly hyperproliferative psoriasis. The latter shows delayed responsiveness to topical therapy with salt-water bathing plus UVB irradiation.

Seabirds at risk around offshore oil platforms in the north-west Atlantic.

Seabirds aggregate around oil drilling platforms and rigs in above average numbers due to night lighting, flaring, food and other visual cues. Bird mortality has been documented due to impact on the structure, oiling and incineration by the flare. The environmental circumstances for offshore hydrocarbon development in North-west Atlantic are unique because of the harsh climate, cold waters and because enormous seabird concentrations inhabit and move through the Grand Banks in autumn (storm-petrels, Oceanodroma spp), winter (dovekies, Alle alle, murres, Uria spp), spring and summer (shearwaters, Puffinus spp). Many species are planktivorous and attracted to artificial light sources. Most of the seabirds in the region are long-distance migrants, and hydrocarbon development in the North-west Atlantic could affect both regional and global breeding populations. Regulators need to take responsibility for these circumstances. It is essential to implement comprehensive, independent arm's length monitoring of potential avian impacts of offshore hydrocarbon platforms in the North-west Atlantic. This should include quantifying and determining the nature, timing and extent of bird mortality caused by these structures. Based on existing evidence of potential impacts of offshore hydrocarbon platforms on seabirds, it is difficult to understand why this has not been, and is not being, systematically implemented.

[Spatial distribution of light intensity under a phototherapy unit]. / Uber die räumliche Verteilung der Lichtintensität unter einer Phototherapie-Einheit.

The distribution of energy under a phototherapy unit containing 8 tubes is uneven; a significant maximum in energy is observed at the centre of the unit. It is therefore desirable to situate the baby at this point of maximum energy. The presence of lateral reflectors however (either metal foil or white sheets), result in not only an increase in energy, but also a more even energy distribution. Therefore the necessity of placing the baby at a special position is no longer required.

[Spatial distribution of light intensity with a phototherapy halogen lamp]. / Uber die räumliche Verteilung der Lichtintensität unter einer Phototherapie-Halogenlampe.

The spatial energy distribution under a phototherapy unit fitted with a special halide lamp (ex. Hereaus, "Photo-Therapie 800") is particularly uneven, with a pronounced decrease in energy towards the edges. With a correct positioning of the child in the centre of the luminous cone however, the energy of the effective light is still distinctly higher than that received from a phototherapy unit fitted with 6 blue fluorescent tubes (Philips 20W/52 BAM blue). With the addition of lateral aluminium reflectors, not only is the effective energy intensity increased, but also the spatial energy distribution becomes more even, so that a very exact positioning of the child is no longer required.

[Passive electrical investigations on erythrocytes in dependence of age donars (author's transl)]. / Passive elektrische Untersuchungen an Erythrozyten in Abhängigkeit vom Lebensalter des Spenders.

It was shown by passive electrical investigations, that the behavior of electrical relaxations of red cells depends on age. With increasing age of the human the relaxation time as well as man the exchange effect stability be increased. This results are due to the increasing of the volume and the contents of haemoglobin of the erythrocytes, and may be due to the changing of the charge of the membrane.

Carcinogen substrate specificity of human COX-1 and COX-2.

The activation of carcinogenic aromatic and heterocyclic amines and benzo[a]pyrene-7,8-diol to intracellular electrophiles by prostaglandin H synthase (COX) is well documented for ovine sources of this enzyme. Here, the arachidonic acid-dependent activation of substrates by human (h)COX-1 and-2 is examined, utilizing recombinant enzymes. The COX-dependent activation of benzidine (BZ), 4-aminobiphenyl, (+)benzo[a]pyrene-7,8-diol, (+)benzo[a]pyrene-7,8-diol, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3-methylimidazo [4,5-f]quinoline (IQ), 2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine (PhIP), and 4,4'-methylenebis(2-chloroaniline) (MOCA) is assessed by means of COX-catalyzed, covalent DNA binding. The hCOX isozymes activated all substrates tested, activation varied from barely detectable for IQ (0.76 and 1.52 pmol bound/mg DNA for COX-1 and -2, respectively) to a high of 65 and 117 pmol bound/mg DNA for COX-1 and -2, respectively, for the activation of MOCA. BZ, which is an excellent peroxidase substrate, did not exhibit high DNA binding levels in hCOX assays and this phenomenon was found to be due to high levels of binding to protein, which effectively competed with the DNA for binding in the assay. The demonstrated ability of the COX enzymes to activate a variety of environmental and dietary carcinogens indicates a potential role for COX in the activation pathway of aromatic and heterocyclic amines and polycyclic hydrocarbons at extra-hepatic sites during early or late stages of carcinogenesis.

Morphology of the small intestine of weaned piglets and a novel method for morphometric evaluation.

The intestinal morphology of 7-week-old pigs was investigated by light (LM) and scanning electron microscopy (SEM). The piglets were fed either a semisynthetic or a cereal-based diet. The shapes of the intestinal villi and crypts of the duodenum, jejunum and ileum were examined. The villi were predominantly tongue-shaped. In the duodenum they were also ridged, branched and folded, and in the jejunum they were also leaf-like and ridged. At places with lymph follicles, the surface of the ileum was rugged with meandering fold-like villi. The crypts of the three segments of the small intestine were mainly coiled and sometimes branched. A novel morphometric evaluation method was introduced using the enlargement factors of each villus and crypt surface. The enlargement factor for the villus surface of the duodenum, jejunum and ileum was 3.13, 3.72 and 2.71, respectively. The factor for the crypt surface of the duodenum, jejunum and ileum was 9.07, 8.94 and 6.53, respectively. Furthermore, the relative proliferation rate and the epithelial renewal index were calculated for the first time. The relative proliferation rate of the duodenum, jejunum and ileum was 32.88, 34.78 and 50.77 proliferations per mm crypt perimeter, respectively. The diets consumed had an influence on the epithelial renewal index being higher for piglets fed the cereal-based diets.

Peroxidase-catalyzed oxidation of 2,4,6-trichlorophenol.

2,4,6-Trichlorophenol (TCP) is an environmental contaminant that is toxic, mutagenic, and carcinogenic. We have investigated peroxidase-catalyzed oxidation of TCP as an alternative pathway of TCP bioactivation using horseradish peroxidase (HRP) as a model peroxidase. TCP was shown to function as a reducing substarte for HRP as evidenced by TCP-dependent, HRP-catalyzed reduction of 5-phenyl-4-penten-1-yl hydroperoxide (PPHP) to its corresponding alcohol. In addition, TCP was shown to undergo hydroperoxide (H2O2, ethyl hydroperoxide, or PPHP)-dependent metabolism as evidenced by electronic absorption spectroscopic analysis of reaction mixtures. A single major product was detected by reverse phase HPLC and was identified as 2,6-dichloro-1,4-benzoquinone (2,6-dichloro-2, 5-cyclohexadiene-1,4-dione, CAS no. 697-91-6) on the basis of electronic absorption spectroscopy, mass spectrometry, and cochromatography with synthetic standard. In addition, HRP-catalyzed oxidation of TCP yielded EPR-detectable phenoxyl radical intermediates whose EPR spectrum consisted of a 1:2:1 triplet characterized by proton hyperfine coupling constants aH(3,5) = 2.35 gauss. Mechanisms for the hydroperoxide-dependent, HRP-catalyzed oxidation of TCP are proposed that are consistent with these results.

Chemical modification of cellulosic membranes and their blood compatibility.

Blood compatibility is determined by interactions at the blood-material interface that depend on the material surface chemical structure. Through selective modifications of the chemically reactive hydroxyl groups of cellulose, the aim was to improve the biocompatibility of cellulose membranes. The number of potentially reactive hydroxyl groups on the cellulose membrane surface were reduced through isocyanate cross-links or through the introduction of hydrophilic, hydrophobic, or ionic functionalities by graft copolymerization. To assess blood compatibility, levels of C3a desArg were determined in plasma after membrane contact. Using the electrophoretic mobility test, the release of cytokines were measured after in-vitro incubation of mononuclear cells with membranes. Adsorption of 131J-human fibrinogen was additionally investigated. With respect to the biocompatibility parameters selected, the modified cellulose membranes show improved in-vitro blood compatibility in comparison to unmodified cellulose membranes.