Pentacene based Onsager crosses.

A dearomatization/aromatization strategy accesses the tetrahedral (crosslike) pentacene tetramer (tetrakis(4-((6,13-bis(TIPS-ethynyl)pentacen-2-yl)ethynyl)phenyl)silane). This molecular caltrop and one of its derivatives form amorphous thin films, demonstrating the impact of the 3D-tetramerization on the bulk morphology of the otherwise crystalline TIPS-pentacene.

The molybdenum cofactor biosynthetic protein Cnx1 complements molybdate-repairable mutants, transfers molybdenum to the metal binding pterin, and is associated with the cytoskeleton.

Molybdenum (Mo) plays an essential role in the active site of all eukaryotic Mo-containing enzymes. In plants, Mo enzymes are important for nitrate assimilation, phytohormone synthesis, and purine catabolism. Mo is bound to a unique metal binding pterin (molybdopterin [MPT]), thereby forming the active Mo cofactor (Moco), which is highly conserved in eukaryotes, eubacteria, and archaebacteria. Here, we describe the function of the two-domain protein Cnx1 from Arabidopsis in the final step of Moco biosynthesis. Cnx1 is constitutively expressed in all organs and in plants grown on different nitrogen sources. Mo-repairable cnxA mutants from Nicotiana plumbaginifolia accumulate MPT and show altered Cnx1 expression. Transformation of cnxA mutants and the corresponding Arabidopsis chl-6 mutant with cnx1 cDNA resulted in functional reconstitution of their Moco deficiency. We also identified a point mutation in the Cnx1 E domain of Arabidopsis chl-6 that causes the molybdate-repairable phenotype. Recombinant Cnx1 protein is capable of synthesizing Moco. The G domain binds and activates MPT, whereas the E domain is essential for activating Mo. In addition, Cnx1 binds to the cytoskeleton in the same way that its mammalian homolog gephyrin does in neuronal cells, which suggests a hypothetical model for anchoring the Moco-synthetic machinery by Cnx1 in plant cells.

[Spectrographic studies on the radioresistance of Miltex and miltefosine]. / Spektrographische Untersuchungen zur Strahlenresistenz von Miltex und Miltefosin.

AIM: With simultaneous application of Miltex and radiation therapy in the combined treatment of topical relapses and skin metastases in breast carcinoma patients the question arises, how radioresistant is the new cytotoxic agent. Because of the long penetration times of the active agent miltefosine the answer is important with particular regard to the time of the external application of Miltex. MATERIAL AND METHOD: After the application of a single dose of 10 Gy we studied the stability of the commercial preparation and its active agent miltefosine by means of absorption spectroscopy. RESULTS: Immediately following the irradiation no alterations in absorption spectra of Miltex and miltefosine were found. However, 2 and 8 h post radiation the absorption curves of Miltex and miltefosine solutions were distinctly changed. The radiation induced changes of Miltex dilutions were smaller than those of the miltefosine solutions. For the commercial preparation the amount of the radiation-induced destruction is 0.10. CONCLUSIONS: Consequently Miltex has shown a sufficient radioresistance or its decrease in the effectiveness is small. With daily single doses of 2 Gy in the radiotherapy of the topical relapses and skin metastases the destruction degree should be reduced to 0.02 assuming linear changes. Because of the distinct changes in the spectra and relative slow penetration of miltefosine in various cell lines [10, 11, 14] we will propose an application of the commercial cytotoxic agent 5 h before the radiation fractions. The smaller effect on Miltex is discussed in relation to the solution mediators of the active agent.

N-acetylneuraminic acid estimation in human serum by neuraminidase and resorcinol/ferric(III) chloride reagent in hydrochloric solution.

By the method described the serum concentration of the protein-bound or the total N-acetylneuraminic acid can be determined. The estimation of the protein-bound N-acetylneuraminic acid is a specific method. In comparison to the Arzneibuch (D.L.) GDR-method (Vol. 2, Akademie Verlag Berlin, 1985) based on Svennerholm (Biochim. Biophys. Acta 24 (1957) 604-611) the advantages of our estimation are: high stability of the dye complex during a period of at least one hour for a final concentration of at least 6.0 mol/l hydrochloric acid; omission of the time-consuming resuspension of the protein precipitation and the extraction of the dye product with n-amyl alcohol; and the lack of diminution of the monosaccharide influence.

Anoxia induces time-independent K+ current through KATP channels in isolated heart cells of the guinea-pig.

1. Isolated ventricular heart cells of the guinea-pig were exposed to anoxia (PO2 < 0.1 Torr) which induced a time-independent K+ current. This current was studied with the patch clamp technique in the whole-cell and cell-attached configuration. 2. The latency until anoxia-induced changes of whole-cell current developed was distributed exponentially (mean 10.5 min; n = 41). The current was abolished within 2-4 s of reoxygenation. 3. The reversal potential of the anoxia-induced change of whole-cell current at 5.4 and 15 mM [K+]o was -82 and -61 mV, respectively. 4. Analysis of current noise in whole-cell current during the phase of the slow development of the anoxia-induced current yielded a slope conductance of unitary currents of 8.1 pS (5.4 mM [K+]o) which is far below the 30 pS of KATP channels in inside-out patches with no Na+ and Mg2+ in the bath. 5. Reduced unitary current induced by anoxia was recorded in single-channel measurements with 10.4 mM-K+ in the pipette. 6. Using 150 mM-K+ in the pipette, anoxia caused unitary inward currents with a slope conductance of 83 pS. The open probability of the channels (P(o)) reached maximum values between 0.6 and 0.95. The channels closed within 1-3 s of reoxygenation. 7. At voltages between -85 and -45 mV and maximum P(o), open time histograms were dominated by a fast exponential (tau 01 = 0.55 +/- 0.21 ms, mean +/- S.D.) and one or two slow exponentials. 8. Voltage ramp experiments showed that single-channel currents were slightly rectifying in the inward direction. 9. Glibenclamide (1 microM) reversibly blocked the anoxia-induced whole-cell and single-channel currents. 10. It is concluded that during anoxia it is only KATP channels which open by a sufficient decrease of submembrane ATP levels.

[Examinations of the analytic reliability of N-acetylneuraminic acid determinations according to the pharmacopoeia of the GDR]. / Untersuchungen zur analytischen Zuverlässigkeit der N-Acetylneuraminsäure-Bestimmung nach Arzneibuch der DDR.

A further investigation of the Arzneibuch (Diagnostic Laboratory Methods) GDR-method for the estimation of N-acetylneuraminic acid was performed. By this was found, that the formation of the dye complex is not still finished after 15 minutes and the reaction product shows an exponential decomposition. The decomposition rate was much greater in the reaction medium than in n-amyl alcohol. By increasing the ferric (III)-chloride concentration the specificity of the method could be essentially improved. With the fivefold ferric (III)-chloride concentration the physiological concentrations of the protein bound monosaccharides of the serum changed the accuracy of the measuring results by less than or equal to 2.0%.

[Effect of ultraviolet light on the UV/VIS absorption spectrum of components of Eagle (MEM) cell culture medium]. / Effekte des ultravioletten Lichtes auf die UV/VIS-Absorptionsspektren der Bestandteile des Zellzuchtmediums nach EAGLE (MEM).

The impact of ultraviolet light on uv/vis absorption spectra of selected individual components of the cell breeding medium according to Eagle (MEM) was investigated. The strongest alterations of light absorption were detected in L-phenylalanine, L-tyrosine and L-tryptophan. Thus, the absorption behaviour of the Eagle (MEM) medium changed post radiation may be attributed to spectrophotometric alterations of absorption in aromatic amino acids. The results are discussed with regard to the effect on the surface charge of erythrocytes.

[Cell electrophoretic and absorption spectrographic investigations of the indirect effect of ultraviolet light on erythrocytes of patients with myocardial infarct and other illnesses]. / Zellelektrophoretische und absorptionsspektrographische Untersuchungen zur indirekten Wirkung ultravioletten Lichtes auf Erythrozyten von Patienten mit Myokardinfarkt und anderen Erkrankungen.

In 34 patients with myocardial infarct, 14 patients with arterial circulatory bleeding disturbances and 12 dialysis patients, blood was diluted immediately after collection by using an Eagle medium (MEM) which had been irradiated by ultraviolet rays. The erythrocytes of patients with myocardial infarct and circulatory bleeding disturbances responded with a mean increase of negative net surface loading by roughly 6% related to the controls in not-irradiated medium. In the erythrocytes of dialysis patients we found no changes of this kind. After ultraviolet irradiation the uv/vis absorption spectra of the Eagle medium showed an increase of extinction depending on the dosage in the short-wave range and a decrease in the long-wave range. Apparently, these uv-induced changes in the Eagle medium secondarily cause an increase of the surface loading of erythrocytes. In patients with arterial circulatory bleeding disturbances this effect which affects the electrostatic relations particularly in the area of terminal flows could contribute to improving the stability of suspension in the blood, thus having a therapeutic importance for these patients as far as their microcirculation is concerned.

[The results of radiotherapy of epicondylitis humeri using different dosages]. / Ergebnisse der Strahlentherapie der Epicondylitis humeri bei unterschiedlicher Dosierung.

In a prospective analysis the effectiveness of roentgen irradiation with minimal doses (daily single doses .03 Gy up to a total dose of 1.5 Gy) was investigated in 207 patients with an epicondylitis humeri. Compared with a group of 92 patients, who were irradiated with higher doses being in general use (weekly 2x single doses 1.0 Gy to a total dose of 4.0 Gy), the therapeutic results show no significant differences. After termination of the first irradiation series an improvement of complaints was seen in half of the patients (48.8% or 50.0%). A further increase of the quota in success to 74.9% or 70.6% was found 6 weeks after termination of irradiation. By reason of radiotherapeutic results, mainly attained in chronic states of epicondylitis humeri after primary conservative therapy without success for months and partly surgical pretreatment, the radiotherapy should be used more frequently than till now, especially in consideration of its slight side-effects and injuries of patients.

[Changes in the concentration of N-acetylneuraminic acid in the blood of patients with bladder cancer during radiotherapy]. / N-Acetylneuraminsäure-Konzentrationsänderungen im Serum von Harnblasenkarzinom-Patienten während der Strahlentherapie.

The N-acetylneuraminic acid (N-ANA) concentration of serum in 24 patients with bladder carcinoma was measured with a modified Arzneibuch (D.L.) GDR-method before, during and after the postoperative radiotherapy. It was found that the N-ANA-concentrations in the patients operated resulted in a dependence from tumor staging already before the radiotherapy. The N-ANA concentration rose with increased staging. A temporary enhancement of the N-ANA-concentration with the maximum between 20. and 25 radiation fractions occurred in patients of staging T3 and relapses as well as with tumor cells being only little differentiated. The results are discussed in relation to the clinical importance.

[Changes in the water and electrolyte contents of human erythrocytes due to Visotrast 370 during I-V urography (author's transl)]. / Veränderungen des Wasser- und Elektrolytgehaltes menschlicher Erythrozyten durch Visotrast 370 bei der i. v. Urographie.

The effect of the contrast medium Visotrast 370 on the water content and volume of erythrocytes, and on the electrolyte levels of plasma and erythrocytes during I-V urography was examined. The measurements were carried out at one, ten and 30 minutes after injection. One minute after injection there was a significant reduction in the water content and volume of the erythrocytes. The levels of sodium and potassium ions in the plasma were reduced ten minutes after contrast injection, but increased in the erythrocytes. After 30 minutes, significant changes could no longer be demonstrated. Possible causes for these changes and their effects on other organs are discussed. Certain practical conclusions are drawn.

In vitro effects of contrast media on the water content of human erythrocytes.

The effect of the concentration of the contrast media Visotrast 370, Dimer X and Adipiodon on the water content of human erythrocytes was analysed in vitro. While a concentration-dependent water discharge (shrinkage) of erythrocytes was found in the presence of Visotrast 370 and Dimer X, the application of Adipiodon caused water uptake (swelling). Possible causes of swelling of red blood cells despite the hyperosmolality of Adipiodon are discussed.