The H2O2-production by polymorphonuclear leucocytes during phagocytosis

Riassunto Si può dimostrare un accumulo di H₂O₂ in leucociti polinucleati di essudato di cavia o di sangue umano durante la fagocitosi in presenza di KCN 2 mM. La produzione di H₂O₂ e l'attività della perossidasi si considerano importanti per l'azione battericida.     

Strukturspezifischer Abbau von Polypeptid-Metall-Komplexen III 1. Abbau des Ni2+-Angiotensin II-Komplexes durch H2O2 2

Summary The octapeptide Val⁵-Angiotensin II-Asp¹--amide is split into characteristic fragments by hydrogen peroxide, when complexed with Ni²⁺; this degradation does not occur with the Cu²⁺ complex, presumably because an active ternary peroxo complex cannot be formed.     

HRP在L-半胱氨酸自组膜上的固定化及其对H2O2的催化还原作用

在金盘电极表面制备L-半胱氨酸(L-Cys)自组装单分子膜,通过调节溶液的酸度使辣根过氧化物酶(HRP)带有正电荷,利用控制电位的方法在L-Cys自组装单分子膜上组装HRP,制备出辣根过氧化物酶/L-半胱氨酸/金电极(HRP/L-Cys/Au),进而研究金表面上固定化HRP的电化学表征方法以及对H2O2的催化还原作用。结果表明,该固定方法能很好地保持酶的催化活性,能有效催化H2O2分解,所制备的HRP/L-Cys/Au电极在2.2×10-5~2.2×10-2mol/L范围内,还原峰电流与H2O2的浓度呈良好线性关系,相关系数为0.996,对H2O2的检测下限为2.2×10-5mol/L,本文为生物分子的固定化提供了一种较好的方法,对生物传感器的研究具有重要意义。     

On the stability and the reactions of the H2O+ ion in aqueous solution

Zusammenfassung Theoretische Überlegungen führen zur Annahme, dass das in der Gasphase wohlbekannte Molekülion H₂O⁺ auch in wässeriger Lösung unter geeigneten Bedingungen eine gewisse Stabilität besitzt. Es ist zu erwarten, dass dieses Ion, welches als protoniertes OH-Radikal aufgefasst werden kann, bei Reaktionen in saurer, wässeriger Lösung eine gewisse Rolle spielt.     

Gonadotrophin-releasing activity of histones H2A and H2B

We report that histones H2A and H2B possess gonadotrophin-releasing activity in vitro and assess the signal transduction pathways involved in these effects. Perifused and incubated rat anterior pituitary (AP) cells were used, and luteinizing hormone (LH) and follicle stimulating hormone (FSH) were measured by RIA. Perifusion of cells with histone H2A (30 μM) or histone H2B (30 μM), markedly stimulated LH release but failed to elicit any FSH response. Cells incubated with 6 or 30 μM histone H2A showed a dose- and time-dependent stimulatory effect on both LH and FSH release which was blocked by 1 μM peptide MB35, an 86–120 amino acid fragment of histone H2A. Incubation of pituitary cells with gonadotrophin-releasing hormone (GnRH) and histones H2A or H2B showed a stimulatory effect on LH and FSH release which was similar to the sum of the separate effects. Trifluoperazine, as well as ethylene glycol bis(b-aminoethyl ether) N,N,N′,N′-tetraacetic acid (EGTA), alone or in the presence of the calcium ionophore A23187, significantly reduced the response of AP cells to histones. Various cyclic adenosine monophosphate (cAMP) enhancers had no effect on histone-stimulated release of gonadotrophins in incubated AP cells. Our results confirm previous evidence that histones may act as hypophysiotrophic signals. Calcium- and diacylglycerol-associated pathways, but not cAMP, appear to participate in these effects. Received 11 August 1997; received after revision 20 January 1998; accepted 26 January 1998     

Über die Wirkung von rac-endo-2-Bornanamin und von verwandten Verbindungen gegen Influenza A2-Virus Asia

Summary rac-endo-2-Bornanamine (1) shows good activity against infections with influenza A₂ virus (Asia) in mice. None of 41 derivatives or analogues was superior to compound1.     

三元体系Mg2+//Cl-,borate-H2O在308.15K时稳定相平衡研究

采用等温溶解法研究了三元体系Mg2+//C1-,borate-H20在308.15 K时的稳定相平衡;测定了上述体系液相中各组份的平衡溶解度及物化性质(密度和pH),根据实验数据绘制了相应相图和物化性质组成图.该体系在308.15 K时有1个共饱点(水氯镁石+镁硼酸盐)、2条饱和溶解度曲线和2个结晶相区,无复盐及固溶体产生.溶液的物化性质随着MgC12浓度的增大而有规律地变化.体系中章氏硼镁石发生转化,MgC12浓度不同,转化最终产物不同.最后,初步探讨了章氏硼镁石的转化机理.     

Synthesis of L-[3-2H,18O]glycerol and its incorporation into the 4-methyl-5-hydroxyethyl thiazole moiety of thiamine byEscherichia coli

Summary L-[3-²H,¹⁸O]glycerol was prepared and fed toEscherichia coli in order to determine the origin of the oxygen atom in the biosynthesized thiazole moiety of thiamine. Measurement by GC-MS of the isotope incorporation into the thiazole from this substrate confirmed that the 2 hydrogens and the oxygen on the C-3 carbon of glycerol are incorporated directly into the thiazole.     

Temperature dependence of ventilation and O2-extraction in the Kittiwake,Rissa tridactyla

Summary At low ambient temperature the Kittiwake,Rissa tridactyla, increased its oxygen consumption, while lung ventilation remained unchanged. A changed breathing pattern (lower frequency and higher tidal volumes) and an increase in the lung O₂-extraction was responsible for the observed decrease in the ventilatory requirement, which may be important because it reduces the respiratory heat loss during cold exposure.The study was supported by the Danish Natural Science Research Council, Gads Fond, Tipsmidlerne and Norsk Polarinstitutt.     

Tagesperiodik des O2-Umsatzes der Rattenleber

Summary There is a 24 h periodicity of the rat liver tissue respiration (Qo₂) with maximal values at about 07.30 h and minimal values at about 17.00 h.

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Auslandsstipendiat der Schweizerischen Regierung (1963/64).

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Die Arbeit wurde unterstützt von der Max-Planck-Gesellschaft zur Förderung der Wissenschaften, Deutschland.     

Three classes of C2H2 zinc finger proteins

C2H2 zinc finger proteins probably comprise the largest family of regulatory proteins in mammals. Most zinc fingers bind to a cognate DNA. In addition to DNA, many of the proteins also bind to RNA or protein, and some bind to RNA only. The binding properties depend on the amino acid sequence of the finger domains and of the linker between fingers, as well as on the higher-order structures and the number of fingers. C2H2 zinc finger proteins contain from 1 to more than 30 figures. Based on the number and the pattern of the fingers, most of the proteins can be classified into one of three groups: triple-C2H2, multiple-adjacent-C2H2, and separated-paired-C2H2 finger proteins. In contrast to proteins with triple-C2H2 fingers, proteins with multiple-adjacent-C2H2 fingers can bind multiple, different ligands. Proteins with a number of separated-paired fingers bind to the target by means of only a single pair.     

The antiviral effect of Keishi-ni-eppi-ichi-to,a tranditional Chinese herbal medicine,on influenza A2(H2N2) virus infection in mice

The antiviral effect of Keishi-ni-eppi-ichi-to (TJS-064), a traditional Chinese herbal medicine, was investigation in mice infected with influenza A₂(H₂N₂) virus. When mice exposed to 5 LD₅₀ dose of the virus were treated orally with a 70 mg/kg dose of TJS-064 1 day before and 1 day and 4 days after the infection, 100% survived over a 25-day experimental period. At the end of this period all the control mice, treated with saline alone, had died; their mean survival time in days (MSD) was 11.2 days. When mice infected with a 10 LD₅₀ dose of the virus were treated with TJS-064, the MSD was >17.4 days and there was a 50% survival rate, while the control group had a MSD of 8.7 days and 0% survival rate. No significant antiviral effect TJS-064 was observed when the agent was administered orally to mice infected with a 100 LD₅₀ or large dose of influenza virus. Pulmonary consolidation, virus titers in lung tissues and HAI titers in sera of infected mice treated with TJS-064 were all significantly lower than those of infected mice treated with saline. Interferon activities were detected in sera of mice treated with the agent at a dose of 100 mg/kg orally. Since viricidal and viristatic activities of the agent against influenza virus were not demonstrated, the antiviral effects of TJS-064 may be expressed through the host's antiviral functions including interferon production.     

H2 receptor antagonists and human granulopoiesis

Summary The effect of 2 H₂ receptor antagonists (ranitidine and cimetidine) on the in vitro growth of human granulomonopoietic precursors (CFU-GM) was studied. Ranitidine, although having an anti H₂ receptor activity much greater than that of cimetidine, displays the same toxicity for CFU-GM.Acknowledgments. This work was supported by CNR, Rome, PFCCN and AIRC, Milan.     

Soybean photosynthesis: simultaneous14CO2 and O2 estimates

Summary A method of estimating the photosynthetic rate of soybean leaves using an oxygen electrode is presented. The procedure is rapid, requires small samples and compares favourably with estimates by other techniques. Light saturation occurs at 1200 E·m^–2·sec^–1. The apparent K_m for HCO ₃ ^– is 3.2 mM at pH 7.6.