Radiation-induced DNA strand breaks in deoxygenated aqueous solutions. The formation of altered sugars as end groups.

Gamma irradiation of DNA in deoxygenated, N2O-saturated aqueous solution leads to three bound altered sugars present as end groups in broken DNA strands. These sugars are linked to the DNA by phosphoric acid ester bonds. Two of the end groups have the structures (4) and (5). (Formula: see text) The third end group after dephosphorylation has structure (3). The formation of the bound sugars (4) and (5) is explained by a mechanism postulated earlier for the formation of free altered sugars. Except for the phosphoric acid ester linkage, the free altered sugars have the same chemical structures as the bound altered sugars.     

Detection and identification of Staphylococcus aureus using magnetic particle enhanced surface plasmon spectroscopy

In this work, an approach for SPR spectroscopy using the ^liSPR system is examined that combines signal amplification by PCR and magnetic nanoparticles in one injection step. Therefore, the synthesis of PCR products was performed on the beads similar to a solid‐phase PCR, termed PCR‐on‐a‐bead. The functionality of this PCR was proven using an enzymatic assay. For validation the detection of oligonucleotides by SPR, an asymmetric PCR product was investigated. A signal increase upon binding of the PCR product to the specific probes was observed. In addition, surface regeneration of the chip was examined and reuse for at least two times ascertained. Amplification of the SPR signal by magnetic beads was verified but no signal was detected for PCR products immobilized on particles prior to injection.     

Conversion of d-fructose into 6-deoxy-d-threo-2,5-hexudiulose by γ-irridation: a chain reaction in the crytalline state

γ-lrradiation of crystalline β-d-fructose yields 6-deoxy-d-threo-2,5-hexodiulose (2) via a chain reaction. The initial G-value at 25° is 38. With decreasing temperature, G(2) decreases strongly; however, no change in G(2) is observed on going to higher temperatures. G(2) is independent of dose rate, but decreases with increasing dose. A mechanism for the formation of 2 is proposed. Although G(2) decreases with increasing dose, γ-irridiation of d-fructose is a convenient method for obtaining 2 on a preparative scale. At a dose of 10₂₁ eV.g^?1, d-fructose is converted into ～6% of 2.     

In vitro activation of complement and contact system by lactic acidosis.

The activation of complement and contact systems occurs in reperfusion injuries with initial tissue hypoxia, and lactic acidosis such as mycardial infarction and birth asphyxia. The aim of our experiment was the formal proof of activation by sole lactic acidosis. Lactic acid was added to blood and plasma samples from 10 healthy volunteers. C5a and factor XIIa were measured by EIA after incubation at 37 degrees C for 1 h. Both concentrations increased (P < 0.0001 by Friedman analysis) in blood and plasma samples with increasing amount of added lactic acid. Lactic acidosis can activate C5 from the complement system and factor XII from the contact system directly, even in the absence of cellular components.