Preparation of high purity labelled Rose-Bengal with radioiodine

The exchange of Rose-Bengal in the mono-sodium salt with elementary¹³¹I in an organic medium allows for the preparation of a labelled product substantially higher in radiochemical purity than that produced by other methods. Purification of the starting material before the labelling process has been done by adsorption chromatography. Under the conditions described a radiochemical yield more than 97% can be obtained within 30–60 minutes. The product was stable during sterilization and storage for 10 days and was found to be free of¹³¹I.     

On the alkaloids of strychnos—xxxvi: The alkaloids of strychnos hirsuta spruce exbentham; two new β-carbolinic alkaloids,strychnohirsutine and tetradehydrostrychnohirsutine

The structures and configurations of two new β-carbolinic alkaloids, strychnohirsutine 1 and tetra-dehydrostrychnohirsutine 2, isolated from stem and root bark of Strychnos hirsuta, were reported. ¹H NMR data of N,O-diacetylstrychnohirsutine 5 and ¹H and ¹³C NMR data of O-acetyltetradehydrostrychnohirsutine 4 were listed. Alkaloid 1 was converted into 2 by catalytic dehydrogenation.     

Special features in the chemical structure of phosphorus isocyanates

The UV and IR absorption spectra and the NMR and NQR spectra of certain isocyanates of three- and four-coordinated phosphorus have been investigated. The reciprocal effect of the phosphorus atom and the NCO group is discussed on the basis of spectral analysis, quantum chemical calculations of the electron systems, and calculations of the normal vibrational forms. Comparison of the (PO) frequencies in the IR spectra of the phosphorus isocyanates with the Taft gives a linear relationship which testifies to the predominant inductive effect of the NCO group on the P(O)R₁R₂ grouping. A similar relationship is observed between the resonance frequency _res in the NMR spectra and for C1P(O)R₁R₂ compounds. The effect of the phosphorus atom on the electronic system in the NCO group is shown by the hypsochromic shift of the absorption band in the210-m region and an appreciable increase in its intensity, compared with alkyl isocyanates. This fact, which agrees with the NMR spectral data and the quantum chemical calculations, indicates the presence of conjugation in the P-N bond. We found the order of the P-N bond to be approximately 1.2. This partial double-bond nature of the P-N bond results from the interaction of the p electrons of nitrogen in the NCO group with the d orbitals of the phosphorus atom.We are grateful to our colleagues at the Kazan Physicotechnical Institute AS USSR A. I. Rivkind, S. G. Salikhov, and I. A. Safin for recording the spectra.     

Phenol Degradation Features in Aqueous Solutions upon Dielectric-Barrier Discharge Treatment

The formation kinetics and mechanism were studied for the intermediate and final products of degradation of aqueous phenol solutions in air and oxygen low-temperature dielectric-barrier discharge plasmas in a reactor with different geometric arrangements of electrodes. It was shown that the plasma-enhanced oxidation of phenol could be described in the general form by the well-known mechanism of enzymatic oxidation of toxic pollutants (-mechanism). The estimated effective rate constant of phenol degradation in an aqueous solution in an ₂ plasma in reactors with the parallel-plate and coaxial arrangement of electrodes was 2.2 × 10^–3 s^–1 and 5.8 × 10^–2 s^–1, respectively. It was found that the potential toxicity of solutions after treatment was 7.5 times lower than that of the untreated solutions.     

cis-UROCANIC ACID FAILED TO AFFECT in vitro HUMAN LANGERHANS CELL ALLOSTIMULATORY FUNCTION

Abstract— -Urocanic acid (UCA) represents the major ultraviolet B (UVB, 290–320 nm)-absorbing component of the skin. Trans-UCA is naturally produced in the stratum corneum and converts to the cis isomer upon UVB irradiation. In this study, we examined the effect of purified cis -UCA (about 99% of cis isomer) on the human Langerhans cell (LC) allostimulatory function by using the mixed epidermal cell-lymphocyte reaction (MELR). We found that addition of increasing amounts (6.5–400 μg/mL) of purified cis-UCA or (rara-UCA did not modify the T-cell response supported by enriched LC (eLC: 8–25% LC) as well as purified LC (pLC: 70–90% LC) suspensions. Because cis-UCA had no effect on the allostimulatory function of untreated LC, we investigated whether this compound could modify T-cell proliferation induced by UVB-irradiated LC. The UVB exposure of eLC or pLC to 100 J/m² significantly inhibited the capacity of both suspensions to mount a T-cell response. However, addition of cis- UCA did not potentiate this UVB-induced immunosuppression. The eLC or pLC were then incubated with cis-UCA for 18 h at 37°C and washed before adding to allogeneic T cells. The obtained proliferative response was similar to that induced by control LC incubated in medium alone, demonstrating that pretreatment with cis -UCA did not alter human LC function. In conclusion, these results strongly suggest that cis-UCA has no direct effect on human LC antigen-presenting function.     

Colorimetric method for the determination of vanadium with tannic acid in water and oils

A new spectrophotometric method was developed to determine vanadium using tannic acid as a complexing reagent to form a coloured reaction product which can easily be extracted by 1-pentanol in the presence of cetylpyridinium. The developed method can successfully be applied to determine trace levels of 10 ng/ml of vanadium in natural waters without any preconcentration step. It can also determine less than 1 mg/kg of vanadium in edible oils and petroleum products.     

Photosensitized processes in vivo: proposed phototherapeutic applications

The use of photosensitizing dyes having intense absorption bands in the 600-900 nm spectral interval opens up new prospects in the field of photochemotherapy, because it allows the illumination of relatively large tissue volumes with no significant damage to photosensitizer-free tissues. Special interest is currently focused on the photodynamic therapy of solid tumors, because of the property of several dyes with a macrocyclic chemical structure (porphyrins, chlorins, phthalocyanines, xanthenes) to accumulate in significant amounts and be retained for prolonged periods of time by neoplastic lesions. Strategies are being developed for enhancing the selectivity of tumor targeting by photosensitizers through the exploitation of functional or biochemical differences between normal and malignant cells.     

Electron impact mass spectrometry of the acetates of zinc,magnesium, cobalt and manganese

The electron impact mass spectra of the acetates of zinc, magnesium, cobalt and manganese have been investigated using a direct inlet probe. Volatile tetrahedral complexes are produced on heating, and ions of the form [M₄(OCOCH₃)₆O]^+˙ (M = Co and Mn) and [N₄(OCOCH₃)₅O]⁺ (N = Zn or Mg) are observed. A mixture of magnesium and cobalt acetates produces ions of the form [Mg_nCo_4–n(OCOCH₃)₆O]^+˙.     

A ten-residue fragment of an antibody (mini-antibody) directed against lysozyme as ligand in immunoaffinity chromatography

The interaction between an antibody molecule and a protein antigen is an example of "natural" protein modelling. Amino acids of the antigen-binding site consisting of three hypervariable segments (L1, L2, L3) of the light (L) and three (H1, H2, H3) of the heavy (H) chain of an antibody molecule interact with amino acids present in an epitope of a protein. A ten-residue peptide was synthesized with an amino acid sequence analogous to the hypervariable L3 segment of a monoclonal antibody directed against lysozyme. The peptide was immobilized on CH-Sepharose 4B and the affinity adsorbent was used to purify lysozyme added to a detergent extract of insect cells infected with a recombinant baculovirus. This methodology may also be applicable to other antigen-antibody combinations, in immunoaffinity chromatography for selective purification of a protein or in an immunosensor for detection of a protein.