Late effects of radiotherapy in children

PURPOSE: To examine benzoporphyrin derivative angiography as a modality for studying photosensitizer biodistribution in experimental choroidal melanomas. METHODS: A liposomal preparation of benzoporphyrin derivative was used in this study. Digital benzoporphyrin derivative angiograms were performed in 10 rabbits (six for experimental choroidal melanomas, two for normal choroids, and two for irides) using a Topcon ImageNet H1024 digital imaging system, a Kodak Megaplus video camera, and a Topcon TRC-50-VT fundus camera. Only one eye from each rabbit was used. Filters specifically designed for benzoporphyrin derivative (peak absorption at 580 nm and peak emission at 695 nm) were used. Benzoporphyrin derivative (1 mg/kg) was injected into an ear vein while images of tumor, normal choroid, or iris were being obtained. Follow-up images were obtained during the first 3 hours and at 24 hours after injection. Fluorescence microscopy was performed in all 10 rabbits using 1 mg/kg of benzoporphyrin derivative. Tumor-bearing eyes were enucleated at the same time points that angiograms were performed, and the two sets of results were compared for maximum dye accumulation. RESULTS: Digital angiography demonstrated that maximal benzoporphyrin derivative fluorescence occurred in tumors 15 to 45 minutes after injection. Fluorescence photometry corroborated these results. CONCLUSION: Photosensitizer angiography is a valid modality for determining the optimum treatment time for photodynamic therapy.     

Competency to "cop a plea"

A gas-liquid chromatographic method for the estimation of 2-phenylethylamine in rat brain tissue is described. The procedure involves initial separation of the amine from homogenates with ion-exchange chromatography, subsequent acetylation of the eluate and extraction of the N-acetylated amine with ethyl acetate. The N-acetyl-2-phenylethylamine derivative is then converted to the pentafluoropropionyl derivative and quantitated with electron capture detection. Difficulties involved with alternative separative procedures and derivative formation are discussed.     

Second derivative spectrophotometry as an effective tool for examining phenylalanine residues in proteins

The second derivative absorption spectra of N-acetyl ethyl esters of phenylalanine, tyrosine and tryptophan, as models of the aromatic amino acid residues in proteins, were measured. The second derivative spectra of tyrosine and tryptophan were found to have no influence on the spectrum of phenylalanine over the range of 245 to 270 nm, where characteristic absorbance bands of phenylalanine were observed. Thus the second derivative spectrum is a good tool for examining the optical properties of phenylalanine residues in proteins.     

纤维素及其衍生物对金属离子吸附性能的研究进展

纤维素衍生物的吸附性主要是通过对金属离子选择性吸收而体现出来的,文中针对纤维素及其衍生物能够吸附不同的金属离子的性能,综述了近十几年来纤维素及其衍生物对黑色金属离子,轻金属离子和重金属离子的吸附状况和应用情况,简单总结了纤维素衍生物金属离子吸附剂的再生利用,展望了纤维素衍生物金属离子吸附剂在其他方面应用的良好前景.      

The use of N-succinyl derivatives in the study of amino acids and peptides by mass spectrometry

The terminal amino group of amino acids and peptides is blocked as the N-succinyl derivative by reaction with succinic anhydride. The product is then converted to the N,O-permethyl derivative in order to increase its volatility for use in mass spectrometry. The permethylated N-succinyl derivative retains the advantages of the permethylated N-acetyl derivative in regard to ease of preparation on a small scale, volatility and the presence of characteristic fragmentation patterns in their mass spectra. However, peaks in the high mass region are more abundant due to loss of CH3O-from the N-succinyl carbomethoxyl group as well as from the C-terminal carbomethoxyl group. Ions characteristic of the sequence and of individual amino acids are observed, and molecular weight can be determined from the relatively abundant ion at [M--CH3O]+ and from the weak molecular ion.     

5-Br-PADAP导数光度法同时测定铝合金中微量铁和镍

本文用导数光度法同时测定样品中的铁和镍,并对铁、镍络合物二组分的导数光谱性质和测定条件进行了研究,选出其最佳条件,解决了互相干扰问题,进而提出一级导数光度法同时测定铁和镍的新方法。该法简便、快速、用于铝合金样品分析,获得满意的结果。     

Anomalous vessel in the middle ear: the role of CT and MR angiography

The pyrazolo[3,4-b]pyridine derivatives 3 could be prepared by condensing compounds 1 with the 3-aminopyrazolone derivative 2. The pyrazolo[5,2-b]-1,3-oxazine derivative 11 and polyfunctionally substituted 1,4-dihydropyridines 15, 18 were also synthesized. Some of the obtained compounds were tested for their antimicrobial activity.     

Derivatives of the triazoloquinazoline adenosine antagonist (CGS 15943) having high potency at the human A2B and A3 receptor subtypes

The adenosine antagonist 9-chloro-2-(2-furanyl)[1,2,4]triazolo[1, 5-c]quinazolin-5-amine (CGS 15943) binds nonselectively to human A1, A2A, and A3 receptors with high affinity. Acylated derivatives and one alkyl derivative of the 5-amino group and other modifications were prepared in an effort to enhance A2B or A3 subtype potency. In general, distal modifications of the N5-substituent were highly modulatory to potency and selectivity at adenosine receptors, as determined in radioligand binding assays at rat brain A1 and A2A receptors and at recombinant human A3 receptors. In Chinese hamster ovary cells stably transfected with human A2B receptor cDNA, inhibition of agonist-induced cyclic AMP production was measured. An N5-(2-iodophenyl)acetyl derivative was highly selective for A2A receptors. An (R)-N5-alpha-methyl(phenylacetyl) derivative was the most potent derivative at A3 receptors, with a Ki value of 0.36 nM. A bulky N5-diphenylacetyl derivative, 13, displayed a Ki value of 0. 59 nM at human A3 receptors and was moderately selective for that subtype. Thus, a large, nondiscriminating hydrophobic region occurs in the A3 receptor in proximity to the N5-substituent. A series of straight-chain N5-aminoalkylacyl derivatives demonstrated that for A2B receptors the optimal chain length occurs with three methylene groups, i.e., the N5-gamma-aminobutyryl derivative 27 which had a pA2 value of 8.0 but was not selective for A2B receptors. At A1, A2A, and A3 receptors however the optimum occurs with four methylene groups. An N5-pivaloyl derivative, which was less potent than 27 at A1, A2A, and A3 receptors, retained moderate potency at A2B receptors. A molecular model of the 27-A2B receptor complex based on the structure of rhodopsin utilizing a "cross-docking" procedure was developed in order to visualize the environment of the ligand binding site.     

A tale of novel intoxication: seven cases of gamma-hydroxybutyric acid overdose

The chemical behaviours of 4-methyl-2-oxo-2H-benzopyran-7-yl oxoacetyl hydrazine (2) towards some different reagents such as anhydride compounds, aromatic aldehydes, carbon disulphide, and nitrous acid yielded the corresponding pathalazine derivatives (3, 4, 5), hydrazone derivative (6), 1,3,4-oxadiazole derivative (7, 8, 9) and acid azide (10) respectively. Treatment of 10 with absolute alcohols, amines and ethyl amino acid ester gave the corresponding carbamate derivative (11), substituted urea derivative (12) and ethyl substituted alkyl acetate (13) respectively. The biological activity of some synthesized compounds was evaluated.     

Electron capture detection of an apomorphine heptafluorobutyrate derivative at low picogram levels

An electron capturing derivative of apomorphine was prepared by incubating the drug with heptafluorobutyric anhydride (HFBA), triethylamine and heat. Mass spectral analysis suggests that HFBA reacts with both phenolic hydroxyl groups on apomorphine to give a derivative detectable at low picogram levels. This method is sufficiently sensitive for pharmacokinetic studies in the horse and is likely applicable to other dopaminergic analogues of apomorphine.     

Kinetic study on the degradation of prazepam in acidic aqueous solutions by high-performance liquid chromatography and fourth-order derivative ultraviolet spectrophotometry

A reversed-phase HPLC method was developed for the kinetic investigation of the acidic hydrolysis of prazepam which was carried out in hydrochloric acid solutions of 0.01, 0.1 and 1.0 M. In addition, a fourth-order derivative method for monitoring the parent compound itself was proposed and evaluated. One intermediate was observed by HPLC, which should be formed from breakage of the azomethine linkage. Further slow hydrolysis of the amide bond led to the benzophenone product that was isolated and identified. The mechanism of hydrolysis was biphasic, showing a consecutive reaction with a reversible step. Relative standard deviation was less than 2% for HPLC and less than 5% for the derivative method. Detection limits were 1.2 x 10(-7) M for the former method and 6.7 x 10(-7)M for the latter. Accelerated studies at higher temperatures were employed. Results of HPLC and fourth-order derivative methods were statistically the same.     

Synthesis and biological activity of fluorescent yeast pheromones

The mating pheromones of Saccharomyces cerevisiae and derivatives of these pheromones have been synthesized and tested for biological activity in a solution-phase assay. The effects of native alpha-factor and a-factor on the growth of target cells in these assays were identical. A derivative of alpha-factor in which the amino terminus was modified with the fluorescent probe, 6-amino-N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)hexanoyl, was only slightly less active than the unmodified pheromone. Derivatives of a-factor that contain various alkyl groups in place of the farnesyl moiety of the native pheromone were also synthesized and tested for biological activity. A derivative in which the farnesyl moiety is substituted with an unbranched decyl group exhibited activity identical to that of the natural pheromone, whereas a derivative that contains an unbranched pentyl group exhibited significantly lower biological activity than native a-factor. The derivatives of a-factor have in addition been modified to incorporate 6-amino-N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) at the terminus of the alkyl chains. A derivative with the probe attached to a decyl chain displayed activity similar to that of the native pheromone, whereas the same modification on a pentyl chain produced a derivative with very low activity. The fluorescence spectra of the modified alpha-factor and a-factors were measured in methanol, aqueous solution, and aqueous solution containing phospholipid vesicles. The fluorescence of the probes depends on the environment of the pheromones and can be used to monitor the association of the pheromones with the lipid bilayer.     

Comparative orientation of the fluorene residue in native DNA modified by N-acetoxy-N-2-acetylaminofluorene and two 7-halogeno derivatives

Native calf thymus DNA was reacted with N-acetoxy-N-2-acetylaminofluorene (N-AcO-AAF) and its 7-fluoro and 7-iodo derivatives. Different ways of purification of the fluorene modified DNA samples were checked in order ot obtain a nucleic acid free from all noncovalently bound fluorene residues. The decrease in melting temperature in DNA samples modified by N-AcO-AAF(DNA-AAF) was carefully reinvestigated. From these experiments, we conclude that the melting temperature decrease is equal to 1.15 degree C per percent of modified bases, in DNA-AAF samples. Electric dichroism measurements on sonicated DNA samples modified by the different fluorene derivatives show the fluorene ring perpendicular to the helix axis in the case of the N-AcO-AAF and its fluoro derivative, and lying alone the phosphate-sugar backbone in the case of the iodo derivative. The results presented in this paper, along with those obtained earlier, led us to propose an "insertion-denaturation model" for the mode of binding of N-Aco-AAF and its fluoro derivative, and an "outside binding model" for the iodo derivative. Discrepancies with the data obtained by Chang et al.((1974) Biochemistry 13,2142-2148) concerning the melting temperature decrease and the electric dichroism results are observed and discussed.     

Modifications of a macrolide antibiotic midecamycin. II. Reaction of midecamycin and 9-acetylmidecamycin with dimethylsulfoxide and acetic anhydride

Treatment of 9,2'-diacetylmidecamycin (2) with DMSO and acetic anhydride afforded 3'-methylthiomethyl derivative (3) preferably in the presence of pyridine. Reaction of midecamycin (1) with DMSO and acetic anhydride gave 2'-acetyl-9-dehydro-3'-methylthiomethyl derivative (9) indicating that the three hydroxyl groups reacted in a different way to the reagent. When compound 2 was reacted with DMSO and acetic anhydride in the presence of CCl4, 3'-acetoxymethyl derivative (13) was a major product, which was formed via 3 through the Pummerer rearrangement. The structures of 3, 9 and 13 were confirmed by examining NMR and mass spectra of these compounds and their deuterio analogue. They showed antimicrobial spectra similar to 1 but superior in vivo activity.     

Preparation of a crystalline tris-(N-methylpyridinium)-derivative of bovine insulin

The reaction between 2-chloro-N-methylpyridinium iodide and bovine insulin at pH 8.5 afforded a trisubstituted derivative as main product. Following purification on DEAE-Sephadex A-25, this derivative crystallized from a citrate buffer in the form of large rhombohedra very similar to native insulin. This observation was confirmed by zero-layer X-ray precession photography. Amino acid analysis indicated substitution at the B1-terminus and on two of the four tyrosine residues. In the mouse convulsion assay the derivative showed no biological activity.     

Antileishmanial effect of allopurinol. II. Relationship of adenine metabolism in Leishmania species to the action of allopurinol

Allopurinol was shown to be effective in vitro against Leishmania mexicana and Leishmania donovani as well as against Leishmania braziliensis. The major metabolic derivative of allopurinol in humans, oxipurinol, also is antileishmanial for L. donovani. The antileishmanial effect of allopurinol and oxipurinol can be specifically reversed by adenine, and its metabolic precursors and derivatives, but by no other purines or their derivative. It is proposed that the adenylosuccinate synthetase or the adenine phosphoribosyltransferase may be sites of action for these agents.     

An oxazine reagent for derivatization of carboxylic acid analytes suitable for liquid chromatographic detection using visible diode laser-induced fluorescence

This study reports the use of Nile Blue, an oxazine dye, as a derivatization reagent that fluoresces in the far-red spectral region and is suitable for derivatization with carboxylic-acid-containing analytes. Model carboxylic acid analytes such as benzoic acid, acetic acid, phenylacetic acid and hexanoic acid have been reacted as acid chlorides to form Nile Blue derivatives. The synthesis product of the Nile Blue benzoic acid derivative was confirmed using electrospray-mass spectrometry, infrared spectrometry, 1H and 13C nuclear magnetic resonance, reversed phase liquid chromatography (RP-HPLC), normal phase-thin layer chromatography, and spectral characterization. The synthesized Nile Blue derivatives, separated from reaction by-products with RP-HPLC, all demonstrated an approximately 10-fold drop in molar absorptivity and relative quantum yield. In addition, a 40 nm increase in Stokes shift was observed. A portion of the fluorescence was regained through post-column ionization of the Nile Blue benzoic acid derivative at pH 12. A RP-HPLC limit of detection of 88.25 fmol on column has been reported with conventional fluorescence detection-post-column ionization of the Nile Blue benzoic acid derivative. A limit of detection of 1.99 fmol on column (3.98 x 10(-11) M) has been demonstrated for the Nile Blue benzoic acid derivative with the use of a laboratory-constructed visible diode laser fluorescence detector.     

Synthetic study on carbocyclic analogues of cyclic ADP-ribose

Cyclic ADP-ribose (cADPR, 1) is a newly discovered general mediator involved in Ca2+ signaling. Carbocyclic analogues of 1, namely, 2 and 3, were designed as a stable isosteres of 1, and their synthesis was studied. The reaction of a triflate 9 which was derived from known diol 4, and inosine derivative 10 gave desired N1-alkyl derivative 11 in 38% yield, and then it was converted to diphosphate derivative 12.     

Octa-alkyl zinc phthalocyanines: potential photosensitizers for use in the photodynamic therapy of cancer

The synthesis, characterization and electronic spectra of a series of nine 1,4,8,11,15,18,22,25-octa-alkyl zinc phthalocyanines (ZnPc), potential photosensitizers for the photodynamic therapy of cancer, are described. The substituents on the phthalocyanine (Pc) macrocycle "red-shift" the absorbance maximum, in cyclohexane, of all nine members of this series to a value of 703 +/- 2 nm, with a corrected fluorescence emission maximum for the octadecyl derivative of 715 nm. The solubilities and degree of aggregation of six examples in cyclohexane have been measured. The highest homologue, the octadecyl derivative, remains essentially unaggregated to a concentration of 1.5 x 10(-4) mol dm-3. the photostability of this Pc has been examined and the compound shown to be sensitive to photooxidation processes which lead to its decomposition to 3,6-bis-decylphthalimide. Known singlet oxygen quenchers inhibit the photodecomposition. In a comparative study, the octadecyl ZnPc underwent a more rapid photodecomposition than the corresponding metal-free derivative.     

Transrectal ultrasonic planimetry of the prostate in relation to age and lower urinary tract symptoms among elderly men in Japan

We investigated the responses to insect prey (dead houseflies) in 24 "derivative groups" of workers of the ant Formica polyctena created by taking sets of 25 workers out of nine larger "initial groups" kept in laboratory without queens and brood during the preceding five months. In the derivative groups the ants ceased to retrieve flies to their nests after a period ranging from few days to several weeks. The duration of that period did not depend on the present size of the derivative group (decreasing as a result of worker mortality), but was positively correlated with the estimated size of the initial group of the tested ants. The readiness to display venom spraying was higher in smaller derivative groups. These data demonstrate that responses of F. polyctena to insect prey are strongly influenced both by the present and the past size of their group.