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At least 37 records · Page 2Linked to original sources
PubMed1994

The configuration and conformation of di-D-fructose anhydride I. The crystal and molecular structure of 3,4,3',4'-tetra-O-acetyl-6,6'-di (triphenylmethyl)-di-D-fructose anhydride I.

The crystal structure of 3,4,3',4'-tetra-O-acetyl- 6,6'-di(triphenylmethyl)-di-D-fructose anhydride I (1) has been determined by single-crystal X-ray diffraction. The crystals are monoclinic, space group P2(1) with a = 16.399(2), b = 9.091(2), c = 17.946(4) A, beta = 103.66(1) degrees, V = 2600(2) A3, and Z = 2. The structure was refined to R = 0.044 and Rw = 0.051 for 4403 observed reflections. The structure analysis of 1 showed that the previously assigned chemical structure of di-D-fructose anhydride I is undoubtedly alpha-D-fructofuranose beta-D-fructofuranose 1,2':2,1'-dianhydride. The conformations of the furanose rings are E5 with P = 59.8 and tau m = 43.2 degrees for D-fructose 1, and 2T3 with P = -34.39 degrees and tau m = 39.64 degrees for D-fructose 2. The two furanose fragments are linked by a 1,4-dioxane ring in a spiro arrangement. The 1,4-dioxane ring has a chair conformation with Cremer-Pople puckering parameters Q = 0.527 A, phi = 72.2 degrees and the a = 14.2 degrees.

Carbohydrate Conformation↗
PubMed1999

Packing similarities of three isosteric molecules: 4,5-dichlorophthalic anhydride, 4,5-dibromophthalic anhydride and 5,6-dichlorobenzfurazan 1-oxide, including three polymorphs of 5,6-dichlorobenzfurazan 1-oxide.

4,5-Dichlorophthalic anhydride (CPA) lies on a twofold axis in space group C2/c; the molecules pack as stacks of two-dimensional sheets. Polymorph A of 5,6-dichlorobenzfurazan 1-oxide (CBF; systematic name 5,6-dichloro-2,1,3-benzoxadiazole 1-oxide) is isomorphous with CPA with disordered CBF molecules being pseudo-isosteric with the CPA molecule. Polymorph C of CBF has similar unit-cell dimensions but the arrangement of the molecules in the cell is different. 4,5-Dibromophthalic anhydride occurs in space group P1; in a structure derived from the CPA structure. The four structures all have similar two-dimensional sheets of molecules, but differ, in addition to the disorder of the CBF molecules, in the stacking of successive sheets. There are three polymorphs of 5,6-dichlorobenzfurazan 1-oxide. In all three the molecules are disordered about twofold or pseudo-twofold axes. In all three the molecules form chains involving similar Cl.O contacts along the direction of the twofold axis. In polymorphs A and C these chains form virtually identical two-dimensional sheets with inter-chain C-H.O, C-H.N and Cl.Cl contacts, but with different stacking arrangements between the sheets. In polymorph B the chains are associated in face-to-face pairs with the same face-to-face overlap as in A, at an average distance of 3.42 Å compared to an average distance of 3.38 Å in A (cf. Table 8); there are no two-dimensional sheets.

Journal Article↗
PubMed1984

A comparison of the cyclic anhydride and mixed anhydride methods for 111In-DTPA chelation to monoclonal antibodies.

The cyclic anhydride (CA) and the mixed anhydride (MA) of DTPA were synthesized and used to chelate 111In to an antimelanoma monoclonal antibody. The CA and MA methods showed mean labeling efficiencies of 25.7 and 20.5%, respectively (p = NS). The binding efficiency of labeled antibody to human melanoma cells in tissue culture also was similar (means = 52 and 50%, respectively, p = NS), as was tumor uptake in nude mice at 96 hrs post-injection (16%-CA vs 12%-MA). The method required less complicated chemical syntheses, much less preparation time, and the product was stable over a much longer period. The results suggest that the CA method is preferable for bifunctional chelate labeling of monoclonal antibodies with 111In-DTPA.

Animals↗
PubMed1978

Human antihapten antibodies in trimellitic anhydride inhalation reactions. Immunoglobulin classes of anti-trimellitic anhydride antibodies and hapten inhibition studies.

Inhalational exposure to trimellitic anhydride (TMA) produces an immediate-type asthmatic or a late respiratory systemic syndrome in certain workers after a latent period of work exposure. TMA has been found to react with proteins to produce a hapten-protein complex (trimellitate [TM] protein) or become hydrolyzed in aqueous, alkaline solutions to produce a salt, NaTM. Using a solid-phase radioimmunoassay technique, antibodies of different Ig classes were detected against TM-protein conjugates. IgE antibody was detected in three of five workers with asthma. IgG and IgA antibodies were detected in most exposed workers but higher levels of antibody were found in symptomatic workers even after long periods without direct TMA exposure. IgM antibody activity against TM-human serum albumin (TM-HSA) was detected but did not differentiate symptomatic from asymptomatic workers. NaTM served as a hapten for study because it does not react with proteins to form a hapten-protein complex as TMA does. The NaTM only partially inhibited IgG antibody activity against TM-HSA and much smaller amounts of TM-HSA than of NaTM were required to neutralize IgG antibody. A similar result was found with TM-ovalbumin. The latter results suggest that some IgG antibody is directed against a TM-protein moiety, probably a TM-amino acid determinant. In contrast to IgG, marked inhibition by NaTM of IgA and IgM antibody against TM-HSA was found in the sera studied.

Anhydrides↗
PubMed1983

The relationship of airborne trimellitic anhydride concentrations to trimellitic anhydride--induced symptoms and immune responses.

Eighteen workers exposed to trimellitic anhydride (TMA) powder were evaluated in 1979. Twelve of these workers were available for longitudinal study until 1982. Annual clinical evaluations and serum radioimmunoassays for total antibody binding and specific IgE binding to 125I-TM-HSA were performed. In 1979, five workers had antibody against TM-HSA. Of these, three workers were diagnosed with the late respiratory systemic syndrome (LRSS) and one worker with TMA-induced allergic rhinitis. The LRSS workers had significantly elevated total antibody binding of 125I-TM-HSA and the worker with rhinitis had significantly elevated specific IgE binding of 125I-TM-HSA per milliliter of serum. Although TMA handling was intermittent throughout the year, average airborne dust concentrations from 1974 to 1978 at job stations of the two heaviest TMA-exposed occupations, operator and assistant operator, were 2.1 and 0.82 mg/m3, respectively. After local exhaust ventilation had been improved, average airborne dust concentrations of TMA at the two latter job stations fell to levels of 0.03 and 0.01 mg/m3, respectively, in 1982. The decrease in TMA exposure coincided with a gradual fall in total antibody binding of 125I-TM-HSA per milliliter in 1982 and symptomatic improvement in the three individuals with the LRSS. The continuous low-level exposure of the worker with TMA rhinitis was sufficient to elicit a rise in specific IgE against TM-HSA from 1.1 ng of 125I-TM-HSA bound per milliliter in 1979 to 2.12 in 1982.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollution↗
PubMed1998

[Hemoglobin alpha chain isoelectric point modification under the action of urea, sodium cyanate, succinic anhydride or diethylene triamine pentaacetic acid anhydride].

A monomeric protein, the hemoglobin alpha chain, was used to compare four protocols for conjugation with diethylene triamine pentaacetic (DTPA) anhydride. Carbamylation and succinylation were also performed. The isoelectric point (pI) was 7.7 for the native protein versus only 5.5 to 7.3 for the five carbamylated derivatives and 4.0 to 7.0 for the six succinylated derivatives. With carbamylation or succinylation, increasing the molar ratio (agent/protein) was associated with a gradual downward pI shift producing trains of bands. This phenomenon did not occur with DTPA conjugation, whose results varied with the method used; only one derivate (pI 6.7) was produced by all four methods, and multiple fine bands with pH values in the vicinity of 3.6 were seen. For the protein, the pI shift varied with the number of groups inserted on the primary amine residues. Also, the shift was larger if the inserted groups carried electrically-charged moieties.

Chelating Agents↗
PubMed2002

Melibiose, difructose anhydride III and difructose anhydride IV enhance net calcium absorption in rat small and large intestinal epithelium by increasing the passage of tight junctions in vitro.

An Ussing chamber technique was used to determine the effects of three indigestible disaccharides on net Ca transport from the luminal side to the basolateral side of isolated preparations of jejunal, ileal, cecal and colonic epithelium in rats. Permeability of Lucifer Yellow (LY) and transepithelial electrical resistance (TEER), which are indicators of intercellular passage of the intestinal mucosa, were also determined. The concentrations of Ca in the serosal and mucosal media were 1.25 mmol/L and 10 mmol/L, respectively. After a 30-min incubation, the net Ca transport, LY passage and TEER were determined. In the control experiment, LY permeability was lowest, and TEER value was highest in the colon. The addition of 1-100 mmol/L melibiose, difructose anhydride (DFA)III, or DFAIV to the mucosal medium increased the net Ca absorption and LY permeability dose-dependently in the jejunum, ileum, cecum and colon preparations. Melibiose decreased TEER dose-dependently in the jejunum and cecum, but not in the ileum and colon. DFAIII decreased TEER dose-dependently in the jejunum, cecum and colon, but not in the ileum. DFAIV decreased TEER dose-dependently in all four intestinal portions. Positive linear relationships were found between net Ca transport and LY passage in all portions of the intestine, whereas negative linear relationships were found between net Ca absorption and TEER. We concluded that the three indigestible saccharides directly affect the epithelial tissue and activate the passage of tight junctions, thereby promoting Ca absorption in the small and large intestine in vitro.

Animals↗