Improved luminescence properties of MoS2 monolayers grown via MOCVD: role of pre-treatment and growth parameters.

Fabrication of transition metal dichalcogenides (TMDCs) via metalorganic chemical vapor deposition (MOCVD) represents one of the most attractive routes to large-scale 2D material layers. Although good homogeneity and electrical conductance have been reported recently, the relation between growth parameters and photoluminescence (PL) intensity-one of the most important parameters for optoelectronic applications-has not yet been discussed for MOCVD TMDCs. In this work, MoS2 is grown via MOCVD on sapphire (0001) substrates using molybdenum hexacarbonyl (Mo(CO)6, MCO) and di-tert-butyl sulphide as precursor materials. A prebake step under H2 atmosphere combined with a reduced MCO precursor flow increases the crystal grain size by one order of magnitude and strongly enhances PL intensity with a clear correlation to the grain size. A decrease of the linewidth of both Raman resonances and PL spectra down to full width at half maxima of 3.2 cm-1 for the E 2g Raman mode and 60 meV for the overall PL spectrum indicate a reduced defect density at optimized growth conditions.

Indole prenyltransferases from fungi: a new enzyme group with high potential for the production of prenylated indole derivatives.

Prenylated indole derivatives are hybrid natural products containing both aromatic and isoprenoid moieties and are widely spread in plants, fungi and bacteria. Some of these complex natural products, e.g. the ergot alkaloids ergotamine and fumigaclavine C as well as the diketopiperazine derivative fumitremorgin C and its biosynthetic precursors tryprostatin A and B, show a wide range of biological and pharmacological activities. Prenyl transfer reactions catalysed by prenyltransferases represent key steps in the biosynthesis of these compounds and often result in formation of products which possess biological activities distinct from their non-prenylated precursors. Recently, a series of putative indole prenyltransferase genes could be identified in the genome sequences of different fungal strains including Aspergillus fumigatus. The gene products show significant sequence similarities to dimethylallyltryptophan synthases from fungi. We have cloned and overexpressed six of these genes, fgaPT1, fgaPT2, ftmPT1, ftmPT2, 7-dmats and cdpNPT from A. fumigatus in E. coli and S. cerevisiae. The overproduced enzymes were characterised biochemically. Three additional prenyltransferases, DmaW-Cs, TdiB and MaPT were identified and characterised in a Clavicipitalean fungus, Aspergillus nidulans and Malbranchea aurantiaca, respectively. Sequence analysis and alignments with known aromatic prenyltransferases as well as phylogenetic analysis revealed that these enzymes belong to a new group of "aromatic prenyltransferases". They differ clearly from membrane-bound aromatic prenyltransferases from different sources and soluble prenyltransferases from bacteria. The characterised enzymes are soluble proteins, catalyse different prenyl transfer reactions on indole moieties of various substrates and do not require divalent metal ions for their enzymatic reactions. All of the enzymes accepted only dimethylallyl diphosphate as prenyl donor. On the other hand, they showed broad substrate specificity towards their aromatic substrates. Diverse tryptophan derivatives and tryptophan-containing cyclic dipeptides were accepted by these enzymes, providing a new strategy for convenient production of biologically active substances, e.g. by chemoenzymatic synthesis.

Organophosphorus flame retardants and plasticisers in surface waters.

Organophosphates used as flame retardants, plasticisers and lubricants such as tris-(2-chloro-, 1-methyl-ethyl)-phosphate (TCPP), tris-(2-chloroethyl)-phosphate (TCEP) or tris-(2-chloro-, 1-chloromethyl-ethyl)-phosphate (TDCP), tri-n-butylphosphate (TnBP), tri-iso-butylphosphate (TiBP), triphenylphosphate (TPP) and tris-(butoxyethyl)-phosphate (TBEP) have been analysed in several rivers and sewage treatment plant (STP) effluents. The concentrations in the River Ruhr are 20-200 ng/l TCPP, 13-130 ng/l TCEP, about 50 ng/l TDCP, 10-200 ng/l TBEP and up to 40 ng/l TPP. The STP effluents exhibit concentrations up to 400 ng/l TCPP, 130 ng/l TCEP, about 120 ng/l TDCP and 500 ng/l TBEP, respectively. The main sources for the load of organophosphates are sewage treatment plants, but not all contribute equivalent to the amount of inhabitants they serve.

Expression of matrix metalloproteinases and their inhibitors during hepatic tissue repair in the rat.

Matrix metalloproteinases (MMPs) and their specific inhibitors (TIMPs) are thought to play an essential role in liver injury associated with tissue remodeling. However, their distinct expression profile in different liver repair models still remains to be established. Hepatic expression of collagenase (MMP-13), gelatinases A and B (MMP-2, -9), stromelysin-1 and -2 (MMP-3, -10), membrane-type MMP-1 (MMP-14), and TIMP-1 and -2 was studied following single and repeated CCl4-mediated injury and after partial hepatectomy. Expression was analyzed by reverse transcription-PCR (RT-PCR), northern blot analysis, zymography, and immunohistochemistry. Following a single toxic liver injury, MMPs and TIMPs were induced in a distinct time frame in that expression of most MMPs was induced during the early phase of liver injury, was maximal during the inflammatory reaction, and was diminished in the recovery phase. In contrast, TIMP and MMP-2 steady state mRNA levels remained constant in the early phase, were strongly induced during tissue inflammation, and remained increased until the recovery phase. Interestingly, hepatic TNF-alpha expression paralleled the MMP induction profile, while the increase of TGF-beta1 expression mapped to the increase of TIMPs. Chronic liver injury was accompanied by an increase in the steady state mRNA levels of MMP-2 and TIMPs, while other MMPs remained more or less unchanged or were diminished. Partial hepatectomy was followed by a dramatic increase of MMP-14 and to a lesser extent also of TIMP-1 expression; other MMPs and TIMPs were not significantly induced. Liver injury is accompanied by profound changes in hepatic MMP/TIMP expression, the latter being critically dependent on the type of injury. Single toxic injury resulting in complete restoration was characterized by a sequential induction of MMPs and TIMPs suggesting initial matrix breakdown and matrix restoration thereafter. Chronic liver injury leading to fibrosis displays overall diminished matrix degradation mainly through TIMP induction, while liver regeneration induced by partial hepatectomy caused an induction of MMP-14 and TIMP-1 only, which might be unrelated to matrix turnover but connected to pericellular fibrinolysis or fibrolysis required for hepatocellular replication.

Rat liver myofibroblasts and hepatic stellate cells: different cell populations of the fibroblast lineage with fibrogenic potential.

BACKGROUND & AIMS: Hepatic stellate cells (HSCs) are considered the principal matrix-producing cells of the damaged liver. However, other cell types of the fibroblast lineage that have not yet been characterized are also involved in liver tissue repair and fibrogenesis. METHODS: We established cultures of cells of the fibroblast lineage, termed rat liver myofibroblasts, and analyzed their phenotypical and functional properties in comparison with HSCs. RESULTS: HSCs and rat liver myofibroblasts were discernible by morphological criteria and growth behavior. Prolonged subcultivation of rat liver myofibroblasts was achieved, but HSCs were maintained in culture at maximum until second passage. HSCs were characterized by expression of glial fibrillary acidic protein, desmin, and vascular cell adhesion molecule 1, which were almost completely absent in rat liver myofibroblasts. For synthetic properties, HSCs and rat liver myofibroblasts displayed mostly overlapping properties with 4 striking differences. The complement-activating protease P100 and the protease inhibitor alpha(2)-macroglobulin were preferentially expressed by HSCs, whereas interleukin 6-coding messenger RNAs and the extracellular matrix protein fibulin 2 were almost exclusively detectable in rat liver myofibroblasts. CONCLUSIONS: The data show that morphologically and functionally different fibroblastic populations, HSCs and rat liver myofibroblasts, can be derived from liver tissue. HSCs may not represent the single matrix-producing cell type of the fibroblast lineage in the liver.

The complement-activating protease P100 is expressed by hepatocytes and is induced by IL-6 in vitro and during the acute phase reaction in vivo.

Ra reactive factor, a lectin present in the sera of a wide variety of vertebrates, is composed of mannan-binding proteins and a serine protease termed P100, which is known to activate complement. Using differential mRNA display technology to study the "activation"-dependent gene expression of hepatic stellate cells (HSC), we partially cloned a cDNA encoding the rat homolog of P100, which displayed 94% and 88% homology to mouse and human P100 cDNA, respectively. In the rat P100, specific transcripts 5.4, 4.0, and 3.3 kb in size were detected in major amounts in normal liver, but were absent or near the detection limit in other organs. Among the different liver cell populations studied during primary culture, P100-specific transcripts of 4.0 kb were prominent in HSC and present in hepatocytes and hepatoma cells, whereas Kupffer cells and sinusoidal endothelial cells were P100-negative. In addition to 4.0-kb mRNA, freshly isolated hepatocytes also contained transcripts of 5.4 and 3.3 kb, which were down-regulated during primary culture. In situ hybridization of normal liver tissue confirmed the in vitro data in that P100 was expressed by hepatocytes and nonparenchymal liver cells, which probably represent HSC. In vitro P100 steady-state mRNA levels of hepatocytes were stimulated by IL-6 and/or dexamethasone. During the acute phase reaction induced by turpentine injection, P100 steady-state mRNA levels were up-regulated in rat liver. The data demonstrate that: (a) the liver is the primary site for P100 expression in the rat; (b) HSC and hepatocytes appear to represent the cellular sources; and (c) P100 steady-state mRNA levels are up-regulated by the acute phase mediators IL-6 and dexamethasone in vitro and during the acute phase reaction in vivo, suggesting that P100 represents a novel, positive acute-phase gene in the rat.

[Flow cytometry detection of erythrocyte antigens and antibodies. Technical aspects and new clinical applications]. / Durchflusszytofluorometrischer Nachweis von erythrozytären Antigenen und Antikörpern. Technische Aspekte und neue klinische Anwendungen.

BACKGROUND: Although hemagglutination techniques have proved worthwhile since many years in immunohematology, they also have several disadvantages. They are manual and subjective visual methods, which make it difficult to quantitate red cell antibodies or surface antigens. Flow cytometric analysis overcomes these limitations because of its ability to analyze individual populations of cells by sensitive, reproducible, and objective methods. MATERIALS AND METHODS: Washed red cells from regular blood donors and patients were analyzed natively and after treatment with enzymes (sialidase, protease) or pneumococcal polysaccharides, using monoclonal Rh antibodies, human 7s-immunoglobulin, and FITC-labeled anti-human IgG or FITC anti-T lectin. The fluorescence intensity of single red cells was determined in the Ortho Cytoron Absolute flow cytometer. RESULTS: We determined the optimal test conditions and normal values by investigation of 50 blood donors. The fluorescence intensity of untreated red cells proved to be constant and therefore was used to adjust the instrument. Furthermore, the data of experimental adsorptions of red cells with pneumococcal antigens, sialidase (Vibrio cholerae) and protease (papain) as well as data from patients suffering from chronic HBV infection and autoimmune hemolytic anemia and acute pancreatitis are presented. A special software program was developed for statistical analysis and graphical presentation of the raw data. The computer program permits to analyze results from different experiments or from different dates and depicts them comparatively in overlay histograms, which may be useful in a serial study of changes of the antibody concentration or antigen expression. CONCLUSION: The flow cytometric analysis of red cells proves to be a simple, rapid, reproducible, and objective method for antigen and antibody quantitation. Furthermore, this technique may be a useful new tool for the investigation of acute, infection-associated hemolytic anemia.

[Initial results in tumor diagnosis with radioactive lanthanide complexes]. / Erste klinische Erfahrungen bei der Tumordiagnostik mit radioaktiven Lanthanid-Komplexen.

Clinical investigations have been made in 70 patients to determine whether 169Yb-labelled metal ligand complexes accumulate in various tumors as was shown by previous animal experiments. The time course of these radiopharmaceuticals in tumors, the skeleton and the liver permitted a good to excellent tumor imaging in 61/70 cases. Even 2-5 h after intravenous injection of the radioactive compound, a meaningful diagnosis could be made in the majority of cases. A number of lesions were found for which no equivalent findings were available with other methods. They were therefore interpreted as metastases.

[New possibilities in diagnosis of hemolytic diseases in newborns]. / Neue Möglichkeiten bei der Diagnose von hämolytischen Neugeborenenerkrankungen.

The diagnosis and management of the hemolytic disease of the newborn (HDN) rely on measurement of maternal anti-D, amniotic fluid analysis, and fetal blood sampling by cordocentesis. However, amniocentesis and cordocentesis have substantial risks of fetomaternal hemorrhage and subsequent increase in maternal anti-D potency. In addition to quantitation, the functional activity of maternal anti-D has been determined by measuring the interaction of red blood cells sensitized by maternal serum in monocyte-monolayer assays. We assessed the functional activity of anti-D by titration of the sensitized red blood cells using selected sera with rheumatoid factor (RF) as human anti-IgG. First experiments using monoclonal anti-D showed a good correlation between erythrophagocytosis and RF titers. The bilirubin/protein ratio in amniotic fluid may be of great value in predicting the severity of HDN, as shown in 94 cases with severe and 39 cases with moderate disease. Amniotic fluid analysis is complicated by the presence of hemoglobin; we developed a computer program to solve this problem. To improve the serological diagnosis of ABO incompatibility, we measured IgG-anti-A,B in 1,392 maternal and newborn sera applying a sensitive gel test with Coombs serum. Furthermore, we determined the hemolytic activity of anti-A,B by microscopic observation of the morphological changes of red blood cells.

The free vastus lateralis flap: an anatomic study with case reports.

The suitability of the thigh as a donor site for a new free flap was examined in 100 cadavers. It was found that the vastus lateralis muscle can be used to form a myocutaneous or fasciomuscular flap, the raising of which causes no technical problems and leads to no functional and only minor aesthetic impairments. Depending on the muscle segment from which the flap is raised, a neurovascular pedicle measuring between 8 and 20 cm with a diameter of 2 to 2.5 mm (artery) or 2.5 to 4 mm (vein) can be formed. The skin island in the myocutaneous flap measures on average 8 x 16 cm and is located above the middle portion of the muscle. The diameter of the supplying perforator vessel is between 0.7 and 1.2 mm. The flap can be raised parallel to head and neck surgery and applied as a myocutaneous flap for coverage of extensive or perforating defects or intraorally as a fasciomuscular flap.

[New possibilities in diagnosing hemolytic disease of newborn infants]. / Neue Möglichkeiten bei der Diagnose von hämolytischen Neugeborenenerkrankungen.

The diagnosis and management of HDN relies on measurement of maternal anti-D, amniotic fluid analysis and fetal blood sampling by chordiocentesis. However, amniocentesis and chordiocentesis have substantial risks of fetomaternal hemorrhage and subsequent increase in maternal anti-D. In addition to quantitation the functional activity of maternal anti-D has been determined by measuring the interaction of red blood cells sensitized by maternal serum in monocyte-monolayer assays. We assessed the functional activity of anti-D by titration of the sensitized red blood cells using selected sera with rheumatoid factor (RF) as human anti-IgG. First experiments using monoclonal anti-D showed a good correlation between erythrophagocytosis and RF titers. The bilirubin-protein ratio in amniotic fluid may be of great value in predicting the severity of HDN, as shown in 94 cases with severe and 39 cases with moderate disease. Amniotic fluid analysis is complicated by the presence of hemoglobin; we developed a computer program to solve this problem. To improve the serological diagnosis of ABO incompatibility, we measured IgG-anti-A, B in 1,392 maternal and newborn sera applying a sensitive gel test with Coombs serum. Furthermore, we determined the hemolytic activity of anti-A, B by microscopic observation of the morphological changes of red blood cells.

[Analysis of irregular antibodies at the department of transfusion medicine of the Hamburg-Eppendorf University Hospital 1984-1988]. / Analyse irregulärer Antikörper in der Abteilung für Transfusionsmedizin am Universitäts-Krankenhaus Hamburg-Eppendorf von 1984-1988.

In the University Hospital of Hamburg-Eppendorf (UKE) we performed approximately 80,000 screening tests for irregular RBC antibodies in the years 1984-1988. Among 1,815 (2.27%) positive tests, Rhesus and concomitant antibodies occurred in 0.77% (615/80,000), other clinically important antibodies in 0.37% (293 cases). We found significantly less Rh antibodies than in the previous period of the mid seventies (Rh prophylaxis, completely Rh-compatible transfusions).

[Analysis of irregular antibodies in the department of transfusion medicine 1984-1988]. / Analyse irregulärer Antikörper in der Abteilung für Transfusionsmedizin von 1984-1988.

In the University Hospital of Hamburg we performed approximate 80,000 screening tests for irregular RBC antibodies in the years 1984-1988. Among 1,815 (2.27%) positive tests, Rhesus and concomitant antibodies occurred in 0.77% (615/80,000), other clinically important antibodies in 0.37% (293 cases). We found significantly less Rh antibodies than in the previous period of the mid seventies (Rh prophylaxis, completely Rh-compatible transfusions).

Host genetics: a key factor in regulating the distribution of parasites in natural host populations.

The immune response that expels the tapeworm Hymenolepis citelli from the small intestine of its host the white-footed deer mouse is genetically controlled. Patent infections with this tapeworm occur only in individuals that are homozygous for a recessive allele expressed at a single gene locus. By studying this natural host-parasite system in the laboratory it was shown that host genetics contributes to parasite overdispersion in a host population in the absence of all other ecological variables. Thus, the substantive influence of the proportions of resistant and susceptible genotypes in the host population must be considered when developing parasite population models of transmission or control measures.

[Hemolytic disease of the newborn due to ABO incompatibility (author's transl)]. / Hämolytische Neugeborenenerkrankungen infolge ABO-Univerträglichkeit.

Up to now, the exact diagnosis of ABO hemolytic disease of the newborn cannot be made either clinically or serologically. Affected babies are almost all either group A or group B from mothers of group O. In contrast to Rh hemolytic disease the immunological findings do not correlate well with the severity of the clinical course. Sometimes, it is impossible to differentiate between ABO hemolytic disease and non-antibody mediated hyperbilirubinemia. Pathogenetic aspects are discussed which may explain the differences between ABO and Rh hemolytic disease of the newborn. Aids to immunological and clinical diagnosis are given. Ante-natal treatment is not necessary. Indications for and technique of phototherapy and exchange transfusion are presented. Early application of these therapeutical methods prevents bilirubin encephalopathy, kernicterus with subsequent death or development of severe neurological sequelae.

[Neuraminidase induced hemolytic anemia. Experimental and clinical observations (author's transl)]. / Neuraminidase-induzierte Hämolyse. Experimentelle und klinische Untersuchungen

Recently, increasing attention has been focussed on the in vivo action of neuraminidase as possible pathogenetical factor of hemolytic anemia and even hemolytic-uremic syndrome. Neuraminidase action in red cell membranes results in the release of neuraminic acid, and thereby the uncovering of previously hidden receptors, socalled cryptantigens. With special reference to the phythemagglutinin Anti-TAh from the peanut (Arachis hypogae) and the agglutinin Anti-AHP from the albumin gland of the small Helix pomatia we describe some new methods for the detection of these cryptantigens. In addition to the screebubg genagglutination test with Anti-TAh we developed an "Anti-T-consumption test" for quantitative detection of neuraminidase action on red cells. With the purified reagents we developed an indirect fluorescnet antibody method on blood smears for the detection of cryptantigens on single cells. By animal experiments we could show that not only the membranes of red cells but the intima of renal capillaries as well are damaged by neuraminidase. With these new methods we observed 14 patients suffering from hemolytic anemia due to bacterial or viral neuraminidase. Some of these patients developed a hemolytic-uremic syndrome. We believe that the positive reaction with Anti-T Ah should lead to prophylactic heparinization to prevent dissiminated intravascular coagulation. Neuraminidase is the first identified toxin which directly acts on the membranes of red cells and the intima of renal capillaries as well, and thereby in some patients may induce hemolytic-uremic syndrome. Possibly, these results may stimulate the development of further testsystems for the detection of still unknown toxins which are not tested with our reagents, but may equally be involved in the damage of cell membranes.