Novel experimental setup for megahertz X-ray diffraction in a diamond anvil cell at the High Energy Density (HED) instrument of the European X-ray Free-Electron Laser (EuXFEL)

The high-precision X-ray diffraction setup for work with diamond anvil cells (DACs) in interaction chamber 2 (IC2) of the High Energy Density instrument of the European X-ray Free-Electron Laser is described. This includes beamline optics, sample positioning and detector systems located in the multipurpose vacuum chamber. Concepts for pump-probe X-ray diffraction experiments in the DAC are described and their implementation demonstrated during the First User Community Assisted Commissioning experiment. X-ray heating and diffraction of Bi under pressure, obtained using 20 fs X-ray pulses at 17.8 keV and 2.2 MHz repetition, is illustrated through splitting of diffraction peaks, and interpreted employing finite element modeling of the sample chamber in the DAC.

High-resolution inelastic x-ray scattering at the high energy density scientific instrument at the European X-Ray Free-Electron Laser

We introduce a setup to measure high-resolution inelastic x-ray scattering at the High Energy Density scientific instrument at the European X-Ray Free-Electron Laser (XFEL). The setup uses the Si (533) reflection in a channel-cut monochromator and three spherical diced analyzer crystals in near-backscattering geometry to reach a high spectral resolution. An energy resolution of 44 meV is demonstrated for the experimental setup, close to the theoretically achievable minimum resolution. The analyzer crystals and detector are mounted on a curved-rail system, allowing quick and reliable changes in scattering angle without breaking vacuum. The entire setup is designed for operation at 10 Hz, the same repetition rate as the high-power lasers available at the instrument and the fundamental repetition rate of the European XFEL. Among other measurements, it is envisioned that this setup will allow studies of the dynamics of highly transient laser generated states of matter.

Impact of real mirror profiles inside a split-and-delay unit on the spatial intensity profile in pump/probe experiments at the European XFEL

For the High-Energy-Density (HED) beamline at the SASE2 undulator of the European XFEL, a hard X-ray split-and-delay unit (SDU) has been built enabling time-resolved pump/probe experiments with photon energies between 5 keV and 24 keV. The optical layout of the SDU is based on geometrical wavefront splitting and multilayer Bragg mirrors. Maximum delays between Δτ = ±1 ps at 24 keV and Δτ = ±23 ps at 5 keV will be possible. Time-dependent wavefront propagation simulations were performed by means of the Synchrotron Radiation Workshop (SRW) software in order to investigate the impact of the optical layout, including diffraction on the beam splitter and recombiner edges and the three-dimensional topography of all eight mirrors, on the spatio-temporal properties of the XFEL pulses. The radiation is generated from noise by the code FAST which simulates the self-amplified spontaneous emission (SASE) process. A fast Fourier transformation evaluation of the disturbed interference pattern yields for ideal mirror surfaces a coherence time of τc = 0.23 fs and deduces one of τc = 0.21 fs for the real mirrors, thus with an error of Δτ = 0.02 fs which is smaller than the deviation resulting from shot-to-shot fluctuations of SASE2 pulses. The wavefronts are focused by means of compound refractive lenses in order to achieve fluences of a few hundred mJ mm-2 within a spot width of 20 µm (FWHM) diameter. Coherence effects and optics imperfections increase the peak intensity between 200 and 400% for pulse delays within the coherence time. Additionally, the influence of two off-set mirrors in the HED beamline are discussed. Further, we show the fluence distribution for Δz = ±3 mm around the focal spot along the optical axis. The simulations show that the topographies of the mirrors of the SDU are good enough to support X-ray pump/X-ray probe experiments.

An approach for the measurement of the bulk temperature of single crystal diamond using an X-ray free electron laser

We present a method to determine the bulk temperature of a single crystal diamond sample at an X-Ray free electron laser using inelastic X-ray scattering. The experiment was performed at the high energy density instrument at the European XFEL GmbH, Germany. The technique, based on inelastic X-ray scattering and the principle of detailed balance, was demonstrated to give accurate temperature measurements, within [Formula: see text] for both room temperature diamond and heated diamond to 500 K. Here, the temperature was increased in a controlled way using a resistive heater to test theoretical predictions of the scaling of the signal with temperature. The method was tested by validating the energy of the phonon modes with previous measurements made at room temperature using inelastic X-ray scattering and neutron scattering techniques. This technique could be used to determine the bulk temperature in transient systems with a temporal resolution of 50 fs and for which accurate measurements of thermodynamic properties are vital to build accurate equation of state and transport models.

Setup for meV-resolution inelastic X-ray scattering measurements and X-ray diffraction at the Matter in Extreme Conditions endstation at the Linac Coherent Light Source

We describe a setup for performing inelastic X-ray scattering and X-ray diffraction measurements at the Matter in Extreme Conditions (MEC) endstation of the Linac Coherent Light Source. This technique is capable of performing high-, meV-resolution measurements of dynamic ion features in both crystalline and non-crystalline materials. A four-bounce silicon (533) monochromator was used in conjunction with three silicon (533) diced crystal analyzers to provide an energy resolution of ∼50 meV over a range of ∼500 meV in single shot measurements. In addition to the instrument resolution function, we demonstrate the measurement of longitudinal acoustic phonon modes in polycrystalline diamond. Furthermore, this setup may be combined with the high intensity laser drivers available at MEC to create warm dense matter and subsequently measure ion acoustic modes.

A sensitive EUV Schwarzschild microscope for plasma studies with sub-micrometer resolution

We present an extreme ultraviolet (EUV) microscope using a Schwarzschild objective which is optimized for single-shot sub-micrometer imaging of laser-plasma targets. The microscope has been designed and constructed for imaging the scattering from an EUV-heated solid-density hydrogen jet. Imaging of a cryogenic hydrogen target was demonstrated using single pulses of the free-electron laser in Hamburg (FLASH) free-electron laser at a wavelength of 13.5 nm. In a single exposure, we observe a hydrogen jet with ice fragments with a spatial resolution in the sub-micrometer range. In situ EUV imaging is expected to enable novel experimental capabilities for warm dense matter studies of micrometer-sized samples in laser-plasma experiments.

Elemental anomalies in the hippocampal formation after repetitive electrical stimulation: an X-ray fluorescence microscopy study

Our previous studies carried out on the pilocarpine model of seizures showed that highly resolved elemental analysis might be very helpful in the investigation of processes involved in the pathogenesis of epilepsy, such as excitotoxicity or mossy fiber sprouting. In this study, the changes in elemental composition that occurred in the hippocampal formation in the electrical kindling model of seizures were examined to determine the mechanisms responsible for the phenomenon of kindling and spontaneous seizure activity that may occur in this animal model. X-ray fluorescence microscopy was applied for topographic and quantitative analysis of selected elements in tissues taken from rats subjected to repetitive transauricular electroshocks (ES) and controls (N). The detailed comparisons were carried out for sectors 1 and 3 of the Ammon's horn (CA1 and CA3, respectively), the dentate gyrus (DG) and hilus of DG. The obtained results showed only one statistically significant difference between ES and N groups, namely a higher level of Fe was noticed in CA3 region in the kindled animals. However, further analysis of correlations between the elemental levels and quantitative parameters describing electroshock-induced tonic and clonic seizures showed that the areal densities of some elements (Ca, Cu, Zn) strongly depended on the progress of kindling process. The areal density of Cu in CA1 decreased with the cumulative (totaled over 21 stimulation days) intensity and duration of electroshock-induced tonic seizures while Zn level in the hilus of DG was positively correlated with the duration and intensity of both tonic and clonic seizures.

Progress of elemental anomalies of hippocampal formation in the pilocarpine model of temporal lobe epilepsy--an X-ray fluorescence microscopy study

In the present paper, X-ray fluorescence microscopy was applied to follow the processes occurring in rat hippocampal formation during the post-seizure period. In the study, one of the status epilepticus animal models of epilepsy was used, namely the model of temporal lobe epilepsy with pilocarpine-induced seizures. In order to analyze the dynamics of seizure-induced elemental changes, the samples taken from seizure-experiencing animals 3 h and 1, 4, and 7 days after proconvulsive agent administration were analyzed. The obtained results confirmed the utility of X-ray fluorescence microscopy in the research of mechanisms involved in the pathogenesis and progress of epilepsy. The topographic and quantitative elemental analysis of hippocampal formations from different periods of epileptogenesis showed that excitotoxicity, mossy fibers sprouting, and iron-induced oxidative stress may be the processes responsible for seizure-induced neurodegenerative changes and spontaneous recurrent seizures occurring in the chronic phase of the pilocarpine model. The analysis of correlations between the recorded elemental anomalies and quantitative parameters describing animal behavior in the acute period of pilocarpine-induced status epilepticus showed that the areal densities of selected elements measured in the latent period strongly depend on the progress of the acute phase. Especially important seem to be the observations done for Ca and Zn levels which suggest that the intensity of the pathological processes such as excitotoxicity and mossy fibers sprouting depend on the total time of seizure activity. These results as well as dependencies found between the levels of S, K, and Cu and the intensity of maximal seizures clearly confirm how important it is to control the duration and intensity of seizures in clinical practice.

An in situ approach to study trace element partitioning in the laser heated diamond anvil cell

Data on partitioning behavior of elements between different phases at in situ conditions are crucial for the understanding of element mobility especially for geochemical studies. Here, we present results of in situ partitioning of trace elements (Zr, Pd, and Ru) between silicate and iron melts, up to 50 GPa and 4200 K, using a modified laser heated diamond anvil cell (DAC). This new experimental set up allows simultaneous collection of x-ray fluorescence (XRF) and x-ray diffraction (XRD) data as a function of time using the high pressure beamline ID27 (ESRF, France). The technique enables the simultaneous detection of sample melting based to the appearance of diffuse scattering in the XRD pattern, characteristic of the structure factor of liquids, and measurements of elemental partitioning of the sample using XRF, before, during and after laser heating in the DAC. We were able to detect elements concentrations as low as a few ppm level (2-5 ppm) on standard solutions. In situ measurements are complimented by mapping of the chemical partitions of the trace elements after laser heating on the quenched samples to constrain the partitioning data. Our first results indicate a strong partitioning of Pd and Ru into the metallic phase, while Zr remains clearly incompatible with iron. This novel approach extends the pressure and temperature range of partitioning experiments derived from quenched samples from the large volume presses and could bring new insight to the early history of Earth.

X-ray fluorescence analysis of long-term changes in the levels and distributions of trace elements in the rat brain following mechanical injury

This paper describes the results of the application of X-ray fluorescence microscopy to the qualitative, topographic and quantitative elemental analysis of nervous tissue from rats with neocortical brain injury. The tissue samples were analyzed with a 15 μm beam defined by the size of the polycapillary focus. Raster scanning of the samples generated 2D cartographies, revealing the distributions of elements such as P, S, Cl, K, Ca, Fe, Cu, and Zn. Special emphasis was placed on the analysis of the areas neighboring the lesion site and the hippocampal formation tissue. The results obtained for rats with mechanical brain injuries were compared with those recorded for controls and animals with pilocarpine-induced seizures. There were no significant differences in the elemental compositions of gray and white matter between injured and uninjured brain hemispheres. A higher level of Ca was observed in the gray matter of both of the hemispheres in brains with neocortical injuries. A similar relation was noticed for Fe in the white matter. A comparative study of hippocampal formation tissue showed a statistically significant decrease in the mass per unit area of P in the dentate gyrus (DG) and the hilus (H) of DG for animals with brain lesions in comparison with the control group. Analogous relations were found for Cu in the DG and Zn in sector 3 of Ammon’s horn (CA3) and the DG. It is important to note that identical changes in the same areas were observed for animals with pilocarpine-induced seizures in our previous study.

Predictive variables for the biological behaviour of basal cell carcinoma of the face: relevance of morphometry of the nuclei

We did a morphometric analysis of 130 histological sections of basal cell carcinoma (BCC) of the face to find out whether morphometric variables in the structure of the nuclei of BCC cells could serve as predictors of the biological behaviour. We considered the following variables: maximum and minimum diameters, perimeter, nuclear area and five form factors that characterise and quantify the shape of a structure (axis ratio, shape factor, nuclear contour index, nuclear roundness and circumference ratio). We did a statistical analysis of primary and recurring tumours and four histology-based groups (multifocal superficial BCCs, nodular BCCs, sclerosing BCCs and miscellaneous forms) using a two-sided t test for independent samples. Multifocal superficial BCCs showed significantly smaller values for the directly measured variables (maximum and minimum diameters, perimeter and nuclear area). Morphometry could not distinguish between primary and recurring tumours.

[Liver cell culture in bioreactors for in vitro drug studies as an alternative to animal testing]

An important consideration for the utilisation of in vitro culture models for studies on drug metabolism as an alternative to animal testing is the maintenance of a defined degree of cell differentiation. Thus, in vitro conditions reflecting as near as possible the in vivo situation of the cells within the whole organ are required. A bioreactor was developed for the cultivation of liver cells which allows the reorganisation of hepatocytes and non-parenchymal cells of the liver in coculture to form three-dimensional, tissue-like structures including extracellular matrix components produced by the cells. In this study, the vitality and metabolic activity of isolated rat hepatocytes was investigated over a two week culture period in bioreactors. The results show that after a reorganisation phase, the cells preserve specific functions, such as protein and urea synthesis capacity and specific cytochrome P450 activities during the culture period, with maximal values during the first week. Possible applications of the model in pharmaceutical industry are studies on metabolite patterns, enzyme induction, drug-drug-interactions, first pass effects and long-term toxicity of drugs.

In vitro identification of the cytochrome P450 isoform responsible for the metabolism of alpha-dihydroergocryptine

1. The in vitro metabolism of alpha-dihydroergocryptine (DHEC, Almirid), an ergot-derived dopamine agonist for the treatment of Parkinson's disease, has been studied in cultured cell lines following incubation with DHEC. Human hepatocytes as well as two sets of metabolically competent cell lines expressing one single human cytochrome P450 (1A1, 1A2, 1B1, 2A6, 2C8, 2C9, 2C18, 2C19, 2D6, 2E1, 3A4) were used. 2. Mono- and dihydroxy metabolites of DHEC could only be detected in the culture media of the cell line expressing human cytochrome CYP3A4. The same metabolites were found in the media of cultured human hepatocytes derived from three different donors. After 24-h incubation with 1 microM DHEC, approximately 60% mono- and approximately 20% dihydroxy metabolites were detected, i.e. approximately 80% of DHEC was metabolized. Further, DHEC demonstrated an inhibitory effect on CYP3A4-mediated testosterone metabolism and additionally could induce CYP3A4 and CYP2E1 mRNA when added at 10 microM to cultured human hepatocytes. 3. The data suggest that DHEC metabolism in humans is primarily mediated by the CYP3A4 isoform. The results are in accordance with findings derived from other ergot alkaloids.

Effect of phenytoin on cytochrome P450 2B mRNA expression in primary rat astrocyte cultures

Studies on cytochrome P450 2B (CYP2B) in the brain have essentially been focused on protein characterization and regional distribution. Due to the high sequence homology between the closely related CYP2B1 and 2B2 isoforms and the low amounts of the corresponding mRNAs few efforts have been made to analyze the expression, regulation, and inducibility of these P450 genes in a specific cell type. In the present study, we investigated CYP2B mRNA expression in primary rat astrocyte cultures under the influence of the anti-epileptic drug phenytoin, which is known to be a CYP2B inducing agent in liver. In situ hybridization with a digoxigenin (DIG)-labeled cRNA probe demonstrated that 30-40% of the astrocytes strongly expressed a CYP2B mRNA-specific signal within the first week of cultivation. With increasing age (> 14 days) a greater percentage of cells (>90%) expressed mRNA for P450 2B. However, the level of transcriptional activity was substantially lower than in younger cultures. To discriminate between the 2B1 and 2B2 isoforms the reverse transcription/polymerase chain reaction (RT/PCR) procedures were proved for rat hepatic mRNA as a control assay. Subsequently, the application of this method on cultured astrocytes confirmed that these brain cells may express CYP2B1 mRNA. CYP2B2 mRNA could not be detected in astrocyte cultures at any age examined. Phenytoin led to the down regulation of CYP2B1 mRNA, which contrasts with the drug inducing effect on hepatic CYP2B1 and 2B2 levels. After 4 hr of exposure of phenytoin to the astrocytes no amplification product could be detected at all. Phenytoin did not induce either CYP2B1 or 2B2 expression.

Molecular biology of microglia cytokine and chemokine receptors and microglial activation

Activation of brain microglial cells can be subdivided into a number of stages. Early stages likely are proliferation and migration to sites of cell damage. These two stages have been studied exemplarily on the IL-3 receptor beta-subunit and on the CC-chemokine receptor 5 using molecular biological methods. First, IL-3 receptor beta-subunit cDNA has been cloned in full length from rat microglia. Since cultured microglia are already activated to some extent, mRNA of this subunit has been detected in the isolated cells, but was absent in normal rat brain. Lipopolysaccharide (LPS) increased this mRNA in the cultured cells and LPS injected into the circulation of rats induced the mRNA specifically in brain microglia as revealed by in situ hybridizations. Next, we obtained partial cDNAs of receptor-coupled protein tyrosine kinases JAK 1 and JAK 2. These mRNAs were present both in cultured microglia and in rat brain, but were not influenced by LPS. Finally, a full-length cDNA of the rat chemokine receptor 5 has been obtained by PCR methodology. Its mRNA was increased by administration of LPS both in cultured microglia and in vivo. It is expected, that further investigations on these receptors could help to develop improved strategies to combat chronic inflammatory events in the brain.

Lipopolysaccharide induces expression of tumour necrosis factor alpha in rat brain: inhibition by methylprednisolone and by rolipram

1. We have investigated the effects of the phosphodiesterase (PDE) type IV inhibitor rolipram and of the glucocorticoid methylprednisolone on the induction of tumour necrosis factor alpha (TNF-alpha) mRNA and protein in brains of rats after peripheral administration of lipopolysaccharide (LPS). 2. After intravenous administration of LPS, a similar time-dependent induction of both TNF-alpha mRNA and protein was observed in rat brain. Peak mRNA and protein levels were found 7 h after administration of LPS. 3. In situ hybridization experiments with a specific antisense TNF-alpha riboprobe suggested that the cells responsible for TNF-alpha production in the brain were microglia. 4. Intraperitoneal administration of methylprednisolone inhibited the induction of TNF-alpha protein in a dose-dependent manner. A maximal inhibition of TNF-alpha protein production by 42.9+/-10.2% was observed at a dose regimen consisting of two injections of each 30 mg kg(-1) methylprednisolone. 5. Intraperitoneal administration of rolipram also inhibited the induction of TNF-alpha protein in a dose-dependent manner. The maximal inhibition of TNF-alpha protein production was 96.1+/-12.2% and was observed at a dose regimen of three separate injections of each 3 mg kg(-1) rolipram. 6. In situ hybridization experiments showed that the level of TNF-alpha mRNA induced in rat brain by LPS challenge was reduced by intraperitoneal administration of methylprednisolone (2 x 15 mg kg(-1)) and of rolipram (3 x 3 mg kg(-1)). 7. We suggest that peripheral administration of LPS induces a time-dependent expression of TNF-alpha in rat brain, presumably in microglial cells, and that methylprednisolone and rolipram inhibit LPS-induced expression of TNF-alpha in these cells via a decrease of TNF-alpha mRNA stability and/or TNF-alpha gene transcription.

Immune responsiveness of splenocytes after chronic daily melatonin administration in male Syrian hamsters

The interrelationships between the immune system and the pineal hormone, melatonin, have been explored recently. The present studies investigated the effects of daily melatonin injections on reproductive and spleen function in male Syrian hamsters. Testes weights and serum testosterone levels were depressed after 8-10 weeks of daily melatonin injections. Melatonin-treated hamsters exhibited increased splenic lymphoproliferative responses to a polyclonal T-cell mitogen (concanavalin A (Con-A)), but decreased proliferation following stimulation with a polyclonal B-cell mitogen (lipopolysaccharide). It appears that daily melatonin injections in male hamsters increase the T-cell-mediated immune capacity while reducing the antibody-mediated immune potential. These data suggest that chronic, daily melatonin alters immune system responsiveness in hamsters by shifting the balance of cellular and humoral reactivity.

Expression of tumor necrosis factor alpha after focal cerebral ischaemia in the rat

Induction of tumor necrosis factor alpha was studied in the brain of rats after focal cerebral ischaemia by occlusion of the left middle cerebral artery. Using a specific antisense riboprobe for in situ hybridization histochemistry, cells positive for tumor necrosis factor alpha messenger RNA were detected within 30 min in the brain regions known to be necrotic within one to two days after onset of ischaemia. Their number increased over a time period of 1-8 h and then declined. Only a few tumor necrosis factor alpha messenger RNA positive cells could be detected four days after the onset of ischaemia. Reverse-transcription polymerase chain reaction experiments showed that maximal increase of tumor necrosis factor alpha messenger RNA level in the ischaemic brain hemisphere occurred 3 h after occlusion of the middle cerebral artery. Immunocytochemical experiments using an anti-tumor necrosis factor alpha antibody showed the presence of tumor necrosis factor alpha immunopositive cells as early as 30 min after occlusion of the middle cerebral artery in the same brain regions where tumor necrosis factor alpha messenger RNA positive cells were detected. Tumor necrosis factor alpha positive cells were highly abundant in the infarcted brain 8-24 h, but only few of them were detectable four days after the onset of ischaemia. Specificity of the anti-tumor necrosis factor alpha antibody and of the induction of tumor necrosis factor alpha protein was confirmed by western blot analysis. Tumor necrosis factor alpha messenger RNA- and protein-positive cells were also detected in the watershed zone and in some structures of the contralateral brain hemisphere. According to their morphology, tumor necrosis factor alpha-positive cells could be identified as microglial cells and macrophages at different states of activation. This assumption was further confirmed by double-labeling studies using the isolectin B4 from Griffonia simplicifolia, a specific microglial/macrophage cell marker. These results demonstrate that expression of tumor necrosis factor alpha is part of an intrinsic inflammatory reaction of the brain after ischaemia.

Acute and chronic effects of melatonin as an anticonvulsant in male gerbils

Melatonin, a hormone produced in the pineal gland and released into the general circulation on a diurnal basis, has been implicated in many behavioral processes, where it has been shown to have anxiolytic, sedative, and anticonvulsant effects. Male gerbils (Meriones unguiculatus) injected daily with melatonin (25 micrograms, s.c.) exhibited a reduced seizure response to pentylenetetrazol (PTZ, 60 mg/kg, s.c.). The present studies determined 1) whether melatonin's effect was related to the time of day that it was administered and 2) whether a single acute injection of melatonin at various doses could produce anticonvulsant activity. Gerbils provided with 13 weeks of daily melatonin injections (25 micrograms, s.c.) exhibited fewer convulsions after PTZ treatment irrespective of the time of day melatonin was injected. In addition, the melatonin-treated gerbils had lower mortality rates (1/12) than the untreated or vehicle-injected gerbils (5/12). On the other hand, single acute injections of melatonin (0.1-10 mg/kg, i.p.) produced no anticonvulsant activity. It appears that the anticonvulsant effects of melatonin occur only after the animals are chronically exposed to the indole. In addition, melatonin's anticonvulsant ability may utilize a different mechanism than those involved in its endocrine effects, since no diurnal difference in melatonin's anticonvulsant activity was observed.

Mapping of the interaction sites of the growth suppressor protein p53 with the regulatory beta-subunit of protein kinase CK2

p53 plays an essential role in cellular growth control. Some of its distinct biological functions are regulated by interaction with cellular proteins. We have previously (Wagner et al., 1994) shown that p53 binds to the regulatory subunit of protein kinase CK2. Using C-terminal protein fragments of p53 we now demonstrate that the region between amino acids 287 and 340 on the polypeptide chain of p53 is critical for binding of p53 to the beta-subunit of CK2. Neither phosphorylation at the p34cdc2 site (aa315) nor at the CK2 site (aa392) is necessary for binding of p53 to the beta-subunit of CK2. Using deletion mutants of the beta-subunit of CK2 we also show that an internal region between amino acids 72 and 149 of the beta-subunit of CK2 is necessary for binding to p53. Thus, this study defines new functional regions on the polypeptide chains of p53 and of protein kinase CK2.

Cloning of rat interleukin-3 receptor beta-subunit from cultured microglia and its mRNA expression in vivo

The high-affinity receptors for interleukin-3 (IL-3), GM-CSF, and IL-5 are composed of a ligand binding (alpha-) and a transducing (beta-) subunit. Two distinct transducing subunits (clones AIC2A and AIC2B) have been cloned from mouse, whereas in humans, only one (common) beta-subunit (beta c) has been found. A PCR-based cloning strategy was used to obtain a full-length cDNA sequence from rat microglia including 5'-untranslated regions. Sequence analysis revealed a number of features indicative of the presence of only one beta-subunit in the rat. Most likely, the new rIL-3R beta cDNA is the rat equivalent of human respective murine (AIC2B) beta c subunits. Regulation of rIL-3R beta mRNA expression was investigated in cultured microglia and in vivo. Purified microglia expressed significant amounts of rIL-3R beta mRNA. Addition of lipopolysaccharide (LPS) resulted in a marked upregulation of rIL-3R beta mRNA within approximately 4 hr. No downregulation was observed within 1 week's treatment. No rIL-3R beta mRNA was detectable in normal rat brain. However, 3 hr after a single injection of LPS into the tail vein of a rat, a marked induction of receptor mRNA occurred in a variety of brain regions. Transcriptional rates subsided significantly after 24 hr. rIL-3R beta mRNA was visualized by in situ hybridizations with cRNA antisense probes in ramified cells formerly characterized as microglial cells. rIL-3R beta mRNA was also induced in rat brain after occlusion of middle cerebral artery (MCAO).(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of interleukin-3 and tumor necrosis factor-beta mRNAs in cultured microglia

The function of interleukin-3 (or multi-CSF) in the hemopoietic system has been studied in great detail. Although its growth promoting activity on brain microglial cells has been confirmed both in vitro and in vivo, its presence in the brain and even in cultured brain cells has repeatedly been questioned. We have shown recently that isolated rat microglia express mRNA(IL-3) and synthesize IL-3 polypeptide. It is shown here by use of the PCR method, that mRNA(IL-3) is found also in C6 glioblastoma, in rat aggregate cultures, and in newborn and adult rat brain. Quantitation of amplified cDNA(IL-3) was achieved by non-competitive RT-PCR using an elongated internal standard. IL-3 messenger RNA was almost undetectable in vivo and low in (serum-free) aggregate cultures. In isolated microglia, mRNA(IL-3) was increased upon treatment with LPS, PHA, with the cytokines IL-1 or TNF-alpha, with retinoic acid, dbcAMP or the phorbol ester TPA. Effects of LPS were inhibited by dexamethasone, while the glucocorticoid by itself had no effect on basal IL-3 expression. LPS increased mRNA(IL-3) in a concentration-dependent manner beginning with 10 pg/ml and reaching plateau levels at 10 ng/ml. LPS also increased mRNAs of TNF-alpha and TNF-beta. TNF-alpha mRNA was already detectable in untreated microglia and LPS-increased levels were sustained for a few days. In contrast, TNF-beta mRNA was observed only between 4 and 16 h of LPS incubation. It was absent in LPS-free microglia, and after 24 h of LPS-treatment or later.(ABSTRACT TRUNCATED AT 250 WORDS)

A new 42-kda protein-binding to the growth suppressor protein-p53

Expression of the growth suppressor gene p53 in Schizosaccharomyces pombe causes growth arrest which can be suppressed by overexpression of a yeast gene termed tms1. The tms1 gene encodes a 37 KDa protein which binds to p53 in vitro and in vivo when p53 was expressed in fission yeast cells. By using antibodies against recombinant tms1 protein we analyzed mammalian cells for the expression of a tms1 related protein. Human, monkey and rat cells exhibited a bright nuclear fluorescence when incubated with the tms1 specific antibody. In addition, we were able to specifically immunoprecipitate a 42 KDa protein which forms complexes with the p53 protein. The specificity of these complexes was demonstrated by coimmunoprecipitation using different monoclonal antibodies against p53, antibodies against yeast tms1 as well as by Western blot analysis. Thus, we found that the mammalian tms1 related protein represents a new p53 binding protein.

Changes of beta-amyloid precursor protein splice patterns in brain cell aggregate cultures

The splice pattern of beta-amyloid precursor protein (beta-APP) has been studied in a variety of neuronal and glial cells and in brain cell aggregate cultures by the polymerase chain reaction (PCR). The brain-typical pattern, in which beta-APP695 is the dominant form, has been found only in aggregate cultures but not in any of the other cell types including neuronal cell lines. Selective elimination of glial cells from aggregates resulted in increased quantities of beta-APP695, whereas removal of neurons led to a reduction of beta-APP695 and to an elevation of beta-APP751 and beta-APP770. This shift of splice pattern was not observed in cocultures of the neuronal cell line PC 12 with primary astrocytes combined in a variety of cellular ratios. Blood serum, which is an essential component of these cultures, tested on aggregates, did not reduce the amount of beta-APP695 or have any marked effects on splice patterns generally. From these results it is concluded that investigations on brain-typical splicing of beta-APP require primary neurons. Neuronal cell lines may be no suitable model systems. Splicing events favoring production of beta-APP695 may mark an important, very early step of amyloid formation in the brain.

Rat microglial interleukin-3

Interleukin-3 (IL-3, multi-CSF) is a growth factor for a variety of hematopoietic progenitor cells. Recently, microglial cells, the resident macrophages of the central nervous system (CNS) have been shown to proliferate in the presence of IL-3 both in vivo and in culture. Data obtained from cultured astrocytes gave rise to the hypothesis that astrocytes synthesize the microglial growth factor. This is the first report identifying rat microglial cells themselves as a source of IL-3. Culture media conditioned by isolated microglia enhanced microglial proliferation above fresh media controls. IL-3 polypeptide was detected in both conditioned media (CM) and in microglial cells by Western blotting and immunoprecipitation. Furthermore, anti-IL-3 antibodies were able to inhibit microglial proliferation induced by conditioned media. mRNAIL-3 was present in single microglial cells as revealed by in situ hybridization. Total RNA prepared from purified microglia yielded a single PCR amplification product. Identity of the PCR product was confirmed by Southern blot hybridization using a cDNAIL-3 probe and by DNA sequencing. Expression of mRNAIL-3 was observed in both absence and presence of lipopolysaccharide, a bacterial endotoxin, that commonly induces expression of inflammatory cytokines and inhibits microglial proliferation. It is concluded that IL-3 expression in ensuring the recruitment of enhanced numbers of immunocompetent cells at sites of lesion. In the light of weak immune reactions in the brain, it is hypothesized that the expression of a characteristic T cell feature in monocyte-derived microglia may be a partial compensation of T cell functions in brain lesions.

On the interaction of p53 with casein kinase-ii

Binding of p53 to cellular and viral proteins seems to be implicated in the regulation of its growth suppressor or oncogenic activity. Casein kinase II is among the proteins which tightly associate with p53 and which phosphorylate p53 at a C-terminal amino acid residue. In the present study we demonstrate that immunopurified full length p53 as well as a C-terminal p53 fragment which comprises the 130 C-terminal amino acids of authentic p53 is phosphorylated by the casein kinase H holoenzyme but not by the catalytic alpha-subunit of casein kinase II alone. Furthermore, we were able to show that the C-terminal p53 fragment binds to the regulatory beta-subunit of casein kinase II but not to the alpha-subunit. Binding of the C-terminal p53 fragment to the beta-subunit is not severely influenced by phosphorylation of p53 by casein kinase II. Thus, our present results demonstrate that p53 binds to the beta-subunit of casein kinase II via C-terminal sequences of the p53 polypeptide chain. Binding of p53 to the regulatory subunit of casein kinase II might be implicated in the regulation of both proteins, p53 and casein kinase II.

Expression of an outwardly rectifying K+ channel in rat microglia cultivated on teflon

Membrane currents of cultured human monocytes and rat microglia were recorded with the whole-cell patch clamp technique. Freshly isolated monocytes or resting (proliferating) microglia express only inwardly rectifying K+ channels. However, incubation in teflon bags leads to the expression of additional, outwardly rectifying K+ channels. The outward K+ conductance of microglial cells was inhibited by intracellular Cs+ and extracellular 4-aminopyridine or tetraethylammonium. Functional similarities with the microglial outwardly rectifying K+ channel were found in the Kn-channel of lymphocytes which has recently been cloned (RGK5). The polymerase chain reaction (PCR) was used to demonstrate the presence of RGK5-like mRNA in microglia.

Editing of a chloroplast mRNA by creation of an initiation codon

Primary mRNA transcripts in several systems are edited by single base substitutions, small deletions or insertions to yield functional messenger RNA species. Mitochondrial mRNAs in particular, including those from plants, seem to be the subject of extensive editing, unlike mRNAs encoded by chloroplast DNA, for which the prediction of amino-acid sequence from the corresponding gene sequence is generally unambiguous. Occasionally, however, an ACG codon appears at the 5' terminus of chloroplast genes, where the initiation codon ATG would be expected. Here we present evidence for a C----U editing that is responsible for the conversion of the ACG codon to an AUG initiation codon in the mRNA transcript from the rpl2 gene of the maize plastome, showing that mRNA editing can also occur in chloroplasts.

A DATA MANAGER for the health information system Berlin

The needs for permanently changing the logical and physical structure of a medical datebase during the development of a health information system have initiated the project of implementing a DATA MANAGER. The concept of the DATA MANAGER covers facilities for the development of the logical data structure model including documentation of the model and programming support for application programs accessing the health information system (HIS) database. The outstanding facilities of the INTERLISP system have been found to be appropriate for writing the DATA MANAGER. A first data structure model, on which the DATA MANAGER will operate, is roughly outlined.

A data structure model for a health information system

The Ministry of Health and Environmental Control of Berlin is developing a Health Information System (HIS) on the basis of a multi-satellite network system, comprising a central, regional, local and functional unit level. The main part of this paper describes the conceptual structure of the Common Data Base (CDB) of HIS with special regard to the patient-oriented medical information originating from the various institutions of the health care system. This structure comprises the following five levels: 1. PATIENT 2. PROBLEM 3. CASE 4. EVENT 5. ACT Each of the levels represents a node in the structure model. A node is an entity with a set of "local properties" being specified for each level, referring to selected data on inferior levels. The structures of these five levels are described in detail. In the last part, so-called "data-manipulation procedures" are treated. These are descriptions covering any data manipulation and represent the basis of data integrity through system controlled transaction with the data base.