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K Pilz

Publications and source records attributed to K Pilz.

15 recordsLinked to original sources
PubMed2001

Polycyclic musk fragrances in different environmental compartments in Berlin (Germany).

The aim of this study was to obtain data about the contamination of different environmental compartments (102 surface water samples, 59 sediment samples and 165 eel samples) by polycyclic musks (HHCB, AHTN, ADBI, AHMI, and ATII) within the framework of an exposure monitoring program. Results for HHCB (Galaxolide) gave the following mean values in areas strongly polluted with sewage: surface water 1.59 micrograms l-1; sediment 0.92 mg kg-1 d.w. and eel 1513 micrograms kg-1 f.w. (in the edible portion) (6471 micrograms kg-1 lipid). The following average concentrations were found in waters hardly contaminated with sewage: surface water 0.07 microgram l-1, sediment < 0.02 mg kg-1 and eel 52 micrograms kg-1 f.w. (445 micrograms kg-1 lipid). Mean concentrations of 6.85 micrograms l-1 (maximum: 13.3 micrograms/l) could be measured at sewage treatment plants' outlets. It could be shown that these polycyclics are highly suited to use as indicators of the degree of contamination of waters with organic substances originating from sewage. A mean bioconcentration factor (BCF) on wet weight of 862 (HHCB) and 1069 (AHTN) for the transfer from water to eel under natural conditions could be calculated. The corresponding BCF-values based on the lipid content of eel were 3504 (HHCB) and 5017 (AHTN).

Berlin↗
PubMed2001

Parvalbumin-containing interneurons of the human cerebral cortex express nicotinic acetylcholine receptor proteins.

Cholinergic fibers from the basal forebrain are known to contact cholinoceptive cortical pyramidal neurons. Recent electrophysiological studies have revealed that nicotinic acetylcholine receptors are also present in human cerebrocortical interneurons. A direct visualization of nicotinic receptor subunits in cortical interneurons has, however, not yet been performed. We have applied double-immunofluorescence using antibodies against parvalbumin --a marker for the Chandelier and basket cell subpopulation of interneurons--and to the alpha4 and alpha7 subunit proteins of the nicotinic acetylcholine receptor. The vast majority of the parvalbuminergic interneurons was immunoreactive for the alpha4 and the alpha7 nicotinic acetylcholine receptor. Provided these receptors would be functional--as suggested by recent electrophysiological findings--the connectivity pattern of cholinergic afferents appears much more complex than thought before. Not only direct cholinergic impact on cortical projection neurons but also the indirect modulation of these by cholinergic corticopetal fibers contacting intrinsic cortical cells would be possible.

Adult↗
PubMed2001

Polycyclic musk fragrances in fish samples from Berlin waterways, Germany.

The contamination of different fish species by polycyclic musks [Galaxolide (HHCB), Tonalide (AHTN), Celestolide (ADBI), Phantolide (AHMI), and Traesolide (ATII) within the frame work of an exposure monitoring programme are reported. A total of 341 fish samples were taken from three waterways in Berlin known to be contaminated to different extents with sewage. The mean levels of musk fragrance compounds reported on a whole weight basis in fish samples were as follows for the most common polycyclic compound, HHCB, in samples (taken from edible parts) of eel caught in waters strongly polluted with sewage levels were 1513 microg/kg (6471 microg/kg lipid) (AHTN: 726 microg/kg and from slightly polluted waters 52 microg/kg (445 microg/kg lipid) (AHTN: only one value above the detection limit). Median concentrations in fish samples were: perch 200 microg/kg (33.3 mg/kg lipid) common bream 1571 microg/kg (90.1 mg/kg lipid), roach 168 microg/kg (13.0 mg/kg lipid), pike 366 and 370 microg/kg (66.5 and 61.7 mg/kg lipid) and for pike perch 190 microg/kg (47.3 mg/kg lipid). ADBI, AHMI and ATII could be determined only in low concentrations (<10% of the total contents of polycyclics in eel). Clear concentration differences were seen between fish samples from waters contaminated at different levels within the programme of biomonitoring. This demonstrated that polycyclic musks are a very good indicator of the level of contamination of a waterway with sewage. Human exposure to these musk fragrances from consumption of contaminated fish was estimated to be low in comparison to direct dermal absorption from the use of fragrance products.

Animals↗
PubMed2000

Cellular expression of alpha7 nicotinic acetylcholine receptor protein in the temporal cortex in Alzheimer's and Parkinson's disease--a stereological approach.

Cognitive deficits in Alzheimer's and Parkinson's disease are closely related to disturbed cholinergic transmission. The decrease of nicotinic acetylcholine receptor protein has been assessed by Western blotting and immunohistochemistry. Stereology, however, has not been used to assess numbers of receptor-expressing human cerebrocortical neurons. Our approach applies a combination of alpha7 subunit-immunohistochemistry with a stereological technique using defined stretches of pial surface as reference standard. The number of alpha7 subunit protein-expressing neurons in the Alzheimer temporal cortices amounted to approximately half of that of controls while numbers in Parkinson patients lay in between. No differences in the total number of neurons were seen. These results corroborate nonstereological studies on Alzheimer cortices and for the first time show a similar decrease in receptor expression in Parkinson's disease. They provide evidence that not only Alzheimer dementia but also cognitive deficits in Parkinson's disease may be related to decreased nicotinic receptor expression.

Aged↗
PubMed2000

Expression of nicotinic acetylcholine receptors in Alzheimer's disease: postmortem investigations and experimental approaches.

Nicotinic ligand binding studies have shown rather early that the cholinoceptive system is affected in Alzheimer's disease (AD). Today, molecular histochemistry enables one to study the nicotinic acetylcholine receptor (nAChR) subunit expression on the cellular level in human autopsy brains, in animal models and in in vitro approaches, thus deciphering the distribution of nAChRs and their role as potential therapeutic targets. The studies on the nAChR expression in the frontal and temporal cortex of AD patients and age-matched controls could demonstrate that both, the numbers of alpha4- and alpha7-immunoreactive neurons and the quantitative amount, in particular of the alpha4 protein, were markedly decreased in AD. Because the number of the corresponding mRNA expressing neurons was unchanged these findings point to a translational/posttranslational rather than a transcriptional event as an underlying cause. This assumption is supported by direct mutation screening of the CHRNA4 gene which showed no functionally important mutations. To get more insight into the underlying mechanisms, two model systems organotypic culture and primary hippocampal culture - have been established, both allowing to mimic nAChR expression in vitro. In ongoing studies the possible impact of beta-amyloid (Abeta) on nAChR expression is tested. Preliminary results obtained from primary cultures point to an impaired nAChR expression following Abeta exposure.

Aged↗
PubMed1999

Modulated structures of Cs2HgCl4: the 5a superstructure at 185 K and the 3c superstructure at 176 K.

Crystalline dicaesium mercury tetrachloride (Cs(2)HgCl(4)) is isomorphous with beta-K(2)SO(4) (space group Pnma, Z = 4) in its normal phase at room temperature. On cooling a sequence of incommensurate and commensurate superstructures occurs, below T = 221 K with modulations parallel to a*, and below 184 K with modulations along c*. The commensurately modulated structures at T = 185 K with q = (1/5)a* and at T = 176 K with q = (1/3)c* were determined using X-ray scattering with synchrotron radiation. The structure at T = 185 K has superspace group Pnma(alpha,0,0)0ss with alpha = 0.2. Lattice parameters were determined as a = 5 x 9.7729 (1), b = 7.5276 (4) and c = 13.3727 (7) Å. Structure refinements converged to R = 0.050 (R = 0.042 for 939 main reflections and R = 0.220 for 307 satellites) for the section t = 0.05 of superspace. The fivefold supercell has space group Pn2(1)a. The structure at T = 176 K has superspace group Pnma(0,0,gamma)0s0 with gamma = 1/3. Lattice parameters were determined as a = 9.789 (3), b = 7.541 (3) and c = 3 x 13.418 (4) Å. Structure refinements converged to R = 0.067 (R = 0.048 for 2130 main reflections, and R = 0.135 for 2382 satellite reflections) for the section t = 0. The threefold supercell has space group P112(1)/a. It is shown that the structures of both low-temperature phases can be characterized as different superstructures of the periodic room-temperature structure. The superstructure of the 5a-modulated phase is analysed in terms of displacements of the Cs atoms, and rotations and distortions of HgCl(4) tetrahedral groups. In the 3c-modulated phase the distortions of the tetrahedra are relaxed, but they are replaced by translations of the tetrahedral groups in addition to rotations.

Journal Article↗
PubMed1999

Solving crystal structures without Fourier mapping. I. Centrosymmetric case. Erratum.

Unfortunately, some printing errors escaped our attention in the proof-reading of our paper [Pilz & Fischer (1998). Acta Cryst. A54, 273-282]. As some of them may cause inconvenience or confusion to readers, they are corrected here: p. 275, equation (6a) should read: Q(i) = [ summation operator(j = 0)(i-1) (-1)(i-j-1)P(i-j)Q(j)]/i. p. 277 (right column), third line after equation (12) should read: Using D(1) [from (10a)] ellipsis. p. 277 (right column), second line after equation (13) should read: ellipsis namely 2(m+n-1). p. 279 (right column), lines 10 and 11 in second paragraph should read: ellipsis sigma(g(h)) = 0.05g(h) (or 0.1g(h), respectively) for ellipsis. p. 279 (right column), fifth line from bottom should read: ellipsis example I (Table 2) ellipsis. p. 280 (right column), third line before Section 3.2 should read: E.g. one of them systematically ellipsis.

Journal Article↗
PubMed1999

Levels of synthetic musks; bromocyclene and PCBs in eel (Anguilla anguilla) and PCBs in sediment samples from some waters of Berlin/Germany.

The purpose of this study was to identify firstly the extent of contamination both of the aquatic biota and of sediments and secondly any regional differences in the concentrations of these compounds. In 1996, polychlorinated biphenyls (PCBs, including their coplanar congeners) were measured in 58 eel and 50 sediment samples. Furthermore, the veterinary pharmacetical bromocyclene and the nitro musks were determined in 84 (1995) and 122 (1996) eel samples. Polycyclic musk fragrances were additionally determined in analyses carried out in 1996. The mean values obtained during the two measurement periods (1995 and 1996) were 24 and 12 micrograms/kg fw. for musk xylene, 41 and 39 micrograms/kg fw. for musk ketone, 14 and 7 micrograms/kg fw. for bromocyclene and, in 1996, 592 micrograms/kg fw. for HHCB (maximum: 4131 micrograms/kg fw.). Decreasing contamination levels are seen for musk xylene and bromocylene but not for musk ketone. This tendency, and the high amounts of polycyclic musk fragrances in the edible parts of eel show that these musks are widely being used in place of nitro musks and that they reach the aquatic system via waste waters, especially those of sewage treatment plants. The mean levels of PCBs in the biota samples of a highly polluted area were 1227 micrograms/kg fw. or 119 pgTEQ/g (sediment: 203 micrograms/kg dw.) and of a slightly polluted area 340 micrograms/kg fw. or 49 TEQ/g (sediment: 47 micrograms/kg dw.).

Anguilla↗
PubMed1996

Anti-parasitic effector mechanisms in human brain tumor cells: role of interferon-gamma and tumor necrosis factor-alpha.

Toxoplasma gondii, an obligate intracellular parasite, is able to replicate in human brain cells. We recently showed that interferon (IFN)-gamma-activated cells from glioblastoma line 86HG39 were able to restrict Toxoplasma growth. The effector mechanism responsible for this toxoplasmostatic effect was shown by us to be the IFN-gamma-mediated activation of indolamine 2,3-dioxygenase (IDO), resulting in the degradation of the essential amino acid tryptophan. In contrast, glioblastoma 87HG31 was unable to restrict Toxoplasma growth after IFN-gamma activation, and IFN-gamma-mediated IDO activation was weak. We observed that tumor necrosis factor (TNF)-alpha alone is unable to activate IDO or to induce toxoplasmostasis in any glioblastoma cell line tested. Interestingly, we found that TNF-alpha and IFN-gamma were synergistic in the activation of IDO in glioblastoma cells 87HG31, 86HG39 and U373MG and in native astrocytes. This was shown by the measurement of enzyme activity as well as by the detection of IDO mRNA in TNF-alpha + IFN-gamma activated cells. This IDO activity results in a strong toxoplasmostatic effect mediated by glioblastoma cells activated simultaneously by both cytokines. Antibodies directed against TNF-alpha or IFN-gamma were able to inhibit IDO activity as well as the induction of toxoplasmostasis in glioblastoma cells stimulated with both cytokines. Furthermore, it was found that the addition of L-tryptophan to the culture medium completely blocks the antiparasitic effect. We therefore conclude that both TNF-alpha and IFN-gamma may be involved in the defense against cerebral toxoplasmosis by inducing IDO activity as an antiparasitic effector mechanism in brain cells.

Animals↗
PubMed1995

Disturbed planum temporale asymmetry in schizophrenia. A quantitative post-mortem study.

The planum temporale of the temporal cortex was investigated post-mortem in 24 schizophrenic patients and 24 age- and sex-matched control subjects. Schizophrenic patients demonstrated a 20% volume reduction of the left planum temporale (p = 0.032), whereas on the right side, there was a trend for increase in male schizophrenics (+22%, p = 0.17), while in female patients the volume was moderately decreased (-6%, p = 0.74). The mean anterior-posterior diameter of the planum temporale was significantly reduced in the left hemisphere (-20%, p = 0.008), but unchanged on the right side. The asymmetry coefficients (Galaburda et al. (1987) Neuropsychologia 25, 853-868) for the planum temporale cortex volume (p = 0.02) and anterior-posterior diameter (p = 0.002) but not for mean area (p = 0.61) were significantly different between schizophrenics and control subjects. These data support the idea of disturbed cerebral laterality in schizophrenia. The implications of methodology and patient samples are discussed.

Adult↗
PubMed1994

A new, simple, bioassay for human IFN-gamma.

IFN-gamma induces the production of N-formyl-kynurenine from L-tryptophan in various cell types by the induction of the enzyme indoleamine 2,3-dioxygenase (IDO). The IFN-gamma induced IDO activity in the glioblastoma cell line 86HG39 and cells of clone 2D9 derived from this cell line was found to be greater than that in Hela cells and U373MG cells. Consequently 2D9 cells were used in all subsequent experiments. The determination of kynurenine in the supernatant of IFN-gamma activated cells was performed photometrically using a microplate reader. It was found that the amount of kynurenine produced was directly proportional to the amount of IFN-gamma used to activate cells. The detection limit for IFN-gamma of this assay was 20 U/ml. The induction of L-tryptophan degradation was specific for IFN-gamma since neither IFN-alpha, IFN-beta, IL-1, IL-2, IL-6, GM-CSF nor TNF alpha induced the production of detectable amounts of kynurenine by 86HG39 and 2D9 cells. Furthermore, a mab directed against IFN-gamma was able to completely block the IFN-gamma induced IDO activation. This bioassay was used to determine the IFN-gamma content of supernatants harvested from toxoplasma antigen specific human T cell lines and clones. This assay gave reproducible results which correlated well with the IFN-gamma content detected in the same samples using a commercially available ELISA kit. Furthermore in the case of T cell supernatant stimulated 2D9 cells a mab directed against IFN-gamma was able to completely block IDO induction. We conclude that the measurement of kynurenine production induced by IFN-gamma can be used to determinate IFN-gamma content. This is a simple bioassay which can be performed with standard laboratory equipment.

Biological Assay↗
PubMed1994

Lipopolysaccharides and leukotriene B4 induce independently regulated electrophysiological and immunological responses in cultured astrocytes.

Astrocytes play an important role in immunological processes within the central nervous system. They are able to produce cytokines like interleukin 6 (IL-6) and depolarize substantially after stimulation by lipopolysaccharides (LPS) or leukotriene B4 (LTB4). Therefore, we investigated the coupling between these immunological and electrophysiological processes. Amiloride (250 microM), a blocker of various Na+ transport systems, inhibited LPS (5 micrograms/ml)-induced depolarization, whereas the LPS-induced release of IL-6 was unaffected, indicating different intracellular regulatory mechanisms. LTB4 (1.0 microM) induced a depolarization of a similar degree but mediated by a different ionic mechanism and failed to induce a detectable IL-6 release. Dexamethasone (1.0 microM) and cycloheximide (2.0 microM) specifically reduced LTB4-induced depolarization, while LPS-induced depolarization was unaffected, providing further evidence for different regulatory pathways. Neither the depolarization nor the immunological stimuli served as a proliferation signal. These data demonstrate that independent immunological and electrophysiological responses with specific intracellular regulation are evoked after stimulation with LPS or LTB4. With respect to functional disturbance of depolarized glial cells, e.g. in maintaining local ionic homeostasis, neuronal excitability may be affected indirectly and by this way account for the appearance of neurological symptoms during inflammatory CNS diseases.

Animals↗
PubMed1993

Induction of toxoplasmostasis in a human glioblastoma by interferon gamma.

In the course of human toxoplasmosis central nervous system involvement often occurs. As a model for toxoplasma growth within human brain cells the proliferation of Toxoplasma gondii strain BK within the human glioblastoma cell line 86HG39 was analysed. We found that 86HG39 cells support the growth of toxoplasma similar to human monocyte derived macrophages and in contrast to human monocytes. The growth of Toxoplasma gondii within interferon gamma (IFN gamma) treated 86HG39 cells is reduced due to toxoplasmostasis and not due to toxoplasmocide effects. The mechanism of IFN gamma induced toxoplasmostasis was also investigated. It was found that IFN gamma did not induce O2- production and/or nitrite oxide production, and inhibitors of O2- and NO2- did not influence IFN gamma induced toxoplasmostasis. In contrast, the supplementation of L-tryptophan to the culture medium completely abolished the IFN gamma effect. We therefore conclude that the induction of L-tryptophan degradation in 86HG39 cells by IFN gamma, possibly by activation of the indoleamine-2,3-dioxygenase, is responsible for the IFN gamma induced toxoplasmostasis within the glioblastoma cell line.

Animals↗