113 research outputs found
Expression of plasma prekallikrein mRNA in human nonhepatic tissues and cell lineages suggests special local functions of the enzyme
At present it is generally accepted that plasma prekallikrein (PPK) is synthesized in the liver and secreted into the bloodstream. Surprisingly, it has recently been shown that PPK mRNA is present also in RNA from the kidney, adrenal gland and placenta. In spite of its novelty and possible important physiological implications this finding has been neglected. Here we report that PPK mRNA is expressed also in the human brain, heart, lung, trachea, endothelial cells and leukocytes as well as in a variety of fibroblast and epithelial cell lines. Expression of PPK mRNA in fibroblasts, endothelial cells and leukocytes suggests that PPK mRNA detected in RNA preparations from whole tissue may originate solely from these ubiquitously occurring cells. However, PPK mRNA expression in various epithelial cell lines demonstrates that tissue-specific cells also transcribe the PPK gene. The presence of PPK mRNA in nonhepatic tissues and cells indicates that they have the capacity to synthesize the protein. The physiological role of PPK synthesized in extrahepatic tissue is unknown. It may participate in local actions within tissues as well as contributing to the PPK pool in blood plasma. Cultured cells will provide a valuable model for exploring the physiological significance of extrahepatic PPK expression
Die Bedeutung des Messeplatzes Deutschland
Die volkswirtschaftliche Bedeutung des deutschen Messewesens ist grundsätzlich unbestritten, weniger klar ist jedoch die Größenordnung des gesamtwirtschaftlichen Effekts. Auch die Eigentümerstrukturen deutscher Messegesellschaften werden zurzeit diskutiert: Die meisten deutschen Messegesellschaften sind im Eigentum von Städten und Ländern, die sich finanziell sehr unterschiedlich engagieren. Dr. Hermann Kresse, AUMA, sieht die Voraussetzungen für eine komplette Privatisierung des Messegeschäfts gegenwärtig nicht gegeben. Für Prof. Dr. Robert K. von Weizsäcker, Technische Universität München, ist eine Vollprivatisierung der deutschen Messeindustrie der einzig sinnvolle Privatisierungsansatz. Horst Penzkofer, ifo Institut, weist darauf hin, dass Veranstaltungsgeschäft und Messeinfrastruktur noch nicht als Wettbewerbseinheit betrachtet werden können: "Während die meisten Messegesellschaften schon wie private Messeveranstalter auf dem Markt agieren und im Veranstaltungsgeschäft Erträge erwirtschaften, somit eine Privatisierung des Durchführungsgeschäfts durchaus vorstellbar ist, sind die Voraussetzungen für eine wettbewerbsadäquate Vermarktung der Immobilien bzw. Messeinfrastruktur zurzeit noch nicht gegeben."Messestandort, Messewirtschaft, Auslandsmesse, Privatisierung, Deutschland
Small proteoglycans of normal adult human kidney: Distinct expression patterns of decorin, biglycan, fibromodulin, and lumican
Small proteoglycans of normal adult human kidney: Distinct expression patterns of decorin, biglycan, fibromodulin, and lumican.BackgroundAmong the members of the small leucine-rich proteoglycan family, decorin, biglycan, and fibromodulin have been proposed to be potent modulators of transforming growth factor-β (TGF-β) activity, thereby playing an important role in the pathogenesis of fibrotic kidney diseases. Furthermore, decorin expression influences the expression of p21WAF1/CIP1, which has been related to kidney hypertrophy and hyperplasia. However, none of the members of this proteoglycan family have been investigated in normal adult human kidney cortex, thus making it impossible to correlate disease-mediated alterations of their expression with the normal situation in vivo.MethodsThe chondroitin/dermatan sulfate proteoglycans, decorin and biglycan, and the keratan sulfate proteoglycans, fibromodulin and lumican, were investigated in normal human adult renal cortex by immunohistochemistry on the light and electron microscopic level and by in situ hybridization. Northern blot and reverse transcription-polymerase chain reaction (RT-PCR) methods were used to get an estimate of their expression in isolated glomeruli. Decorin excretion with the urine was measured by Western blotting.ResultsTwo bands of decorin and a single band of biglycan mRNA were identified in Northern blots of isolated glomeruli. Amplification by RT-PCR was required to detect the signals for fibromodulin and lumican. All four proteoglycans were preferentially expressed in the renal interstitium with accumulations around tubules. Weak expression was found in the mesangial matrix. Biglycan was expressed by glomerular endothelial cells and, together with fibromodulin, was synthesized and deposited in distal tubular cells and collecting ducts. Immunogold labeling indicated the presence of the proteoglycans in the glomerular basement membrane, which was interpreted as a result of glomerular filtration. Indirect evidence suggested tubular reuptake of decorin after glomerular filtration.ConclusionThe data indicate that the different cells of the adult human kidney are characterized by a distinct expression pattern of the four small proteoglycans. It is suggested that these proteoglycans may have distinct pathophysiological roles depending upon whether they are expressed by mesangial cells, endothelial cells, epithelial cells, or cells of the tubulointerstitium
The local structure of OH species on the V2O3(0 0 0 1) surface: a scanned-energy mode photoelectron diffraction study
Scanned-energy mode photoelectron diffraction (PhD), using O 1s photoemission, together with multiple-scattering simulations, have been used to investigate the structure of the hydroxyl species, OH, adsorbed on a V2O3(0 0 0 1) surface. Surface OH species were obtained by two alternative methods; reaction with molecular water and exposure to atomic H resulted in closely similar PhD spectra. Both qualitative assessment and the results of multiple-scattering calculations are consistent with a model in which only the O atoms of outermost layer of the oxide surface are hydroxylated. These results specifically exclude significant coverage of OH species atop the outermost V atoms, i.e. in vanadyl O atom sites. Ab initio density-functional theory cluster calculations provide partial rationalisation of this result, which is discussed the context of the general understanding of this system
Stable Lithium Argon compounds under high pressure
High pressure can fundamentally alter the bonding patterns of chemical elements. Its effects include stimulating elements thought to be “inactive” to form unexpectedly stable compounds with unusual chemical and physical properties. Here, using an unbiased structure search method based on CALYPSO methodology and density functional total energy calculations, the phase stabilities and crystal structures of Li−Ar compounds are systematically investigated at high pressure up to 300 GPa. Two unexpected Li(m)Ar(n) compounds (LiAr and Li(3)Ar) are predicted to be stable above 112 GPa and 119 GPa, respectively. A detailed analysis of the electronic structure of LiAr and Li(3)Ar shows that Ar in these compounds attracts electrons and thus behaves as an oxidizing agent. This is markedly different from the hitherto established chemical reactivity of Ar. Moreover, we predict that the P4/mmm phase of Li(3)Ar has a superconducting transition temperature of 17.6 K at 120 GPa
Reactivity of He with ionic compounds under high pressure
Helium was long thought to be unable to form stable solid compounds, until a recent discovery that helium reacts with sodium at high pressure. Here, the authors demonstrate the driving force for helium reactivity, showing that it can form new compounds under pressure without forming any local chemical bonds
Observation of the γγ→ττ process in Pb+Pb collisions and constraints on the τ -lepton anomalous magnetic moment with the ATLAS detector
This Letter reports the observation of
τ
-lepton-pair production in ultraperipheral lead-lead collisions
Pb
+
Pb
→
Pb
(
γ
γ
→
τ
τ
)
Pb
and constraints on the
τ
-lepton anomalous magnetic moment
a
τ
. The dataset corresponds to an integrated luminosity of
1.44
nb
−
1
of LHC
Pb
+
Pb
collisions at
√
s
NN
=
5.02
TeV
recorded by the ATLAS experiment in 2018. Selected events contain one muon from a
τ
-lepton decay, an electron or charged-particle track(s) from the other
τ
-lepton decay, little additional central-detector activity, and no forward neutrons. The
γ
γ
→
τ
τ
process is observed in
Pb
+
Pb
collisions with a significance exceeding 5 standard deviations and a signal strength of
μ
τ
τ
=
1.0
3
+
0.06
−
0.05
assuming the standard model value for
a
τ
. To measure
a
τ
, a template fit to the muon transverse-momentum distribution from
τ
-lepton candidates is performed, using a dimuon (
γ
γ
→
μ
μ
) control sample to constrain systematic uncertainties. The observed 95% confidence-level interval for
a
τ
is
−
0.057
<
a
τ
<
0.024
- …