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The 2,3,5-triiodobenzoic acid (TIBA) is an iodine contrast agent used for visualization of tissue in X-ray techniques. However, TIBA induces physiological complications like increase in oxygen reactive species (ROS), and consequently, contrast-induced nephropathies. TIBA's antitumor activity was demonstrated in lung cancer, but the subcellular mechanisms involving its activity in tumor cells are still unknown. Thus, the objective of this work was evaluate whether the anti-tumor activity of TIBA involves ROS increase, in tumor lines of non-small cell lung cancer (H460), chronic myeloid leukemia (K562), and its cytotoxicity in normal renal epithelial (VERO). The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide) assay was used for evaluation of cell viability, the H 2 DCFDA (cell-permeant 2',7'-dichlorodihydrofluorescein diacetate) fluorescent probe to evaluate ROS induction, cell cycle analysis was performed using flow cytometry to measure cell death, and immunofluorescence with annexin/7-AAD (7-amino-actinomycin D), to assess the association of cell death with the ROS generation. TIBA decreases cell viability in a dose-dependent manner for the H460 and K562. However, VERO cells showed less response to the drug, with 70% viable cells after 72 h of treatment in the highest concentration of the drug. While the tumor cells with only 20% viable cells. Besides, tumor cells exhibited higher DNA fragmentation, compared to the renal line (VERO with 5% of fragmented DNA, H460 with 26%, and 56% in K562). Finally, TIBA-induced ROS increase and apoptosis in all lines, which is significantly decreased after treatment with the antioxidant N-acetyl-cysteine (NAC). These data demonstrate the relationship between the increased cellular oxidative stress and the anti-tumor action of the TIBA., (© 2021. The Author(s), under exclusive licence to Springer Nature B.V.)

The efficacy of auxinic herbicides, a valuable weed control tool for growers worldwide, has been shown to vary with the time of day in which applications are made. However, little is known about the mechanisms causing this phenomenon. Investigating the differential in planta behavior of these herbicides across different times of application may grant an ability to advise which properties of auxinic herbicides are desirable when applications must be made around the clock. Radiolabeled herbicide experiments demonstrated a likely increase in ATP-binding cassette subfamily B (ABCB)-mediated 2,4-D and dicamba transport in Palmer amaranth (Amaranthus palmeri S. Watson) at simulated dawn compared to mid-day, as dose response models indicated that many orders of magnitude higher concentrations of N-1-naphthylphthalamic acid (NPA) and verapamil, respectively, are required to inhibit translocation by 50% at simulated sunrise compared to mid-day. Gas chromatographic analysis displayed that ethylene evolution in A. palmeri was higher when dicamba was applied during mid-day compared to sunrise. Furthermore, it was found that inhibition of translocation via 2,3,5-triiodobenzoic acid (TIBA) resulted in an increased amount of 2,4-D-induced ethylene evolution at sunrise, and the inhibition of dicamba translocation via NPA reversed the difference in ethylene evolution across time of application. Dawn applications of these herbicides were associated with increased expression of a putative 9-cis-epoxycarotenoid dioxygenase biosynthesis gene NCED1, while there was a notable lack of trends observed across times of day and across herbicides with ACS1, encoding 1-aminocyclopropane-1-carboxylic acid synthase. Overall, this research indicates that translocation is differentially regulated via specific protein-level mechanisms across times of application, and that ethylene release, a chief phytotoxic process involved in the response to auxinic herbicides, is related to translocation. Furthermore, transcriptional regulation of abscisic acid involvement in phytotoxicity and/or translocation are suggested., Competing Interests: No authors have competing interests

Purpose: This study aimed to investigate the impact of the size of X-ray iodinated contrast agent in nano-emulsions, on their toxicity and fate in vivo., Methods: A new compound, triiodobenzoate cholecalciferol, was synthetized, formulated as nano-emulsions, and followed after i.v. administration in mice by X-ray imaging (micro computed tomography). Physicochemical characterization and process optimization allowed identifying a good compromise between X-ray contrasting properties, monodispersity and stability. This also allowed selecting two formulations with different sizes, hydrodynamic diameters of 55 and 100 nm, but exactly the same composition. In vitro experiments were performed on two cell lines, namely hepatocytes (BNL-CL2) and macrophages (RAW264.7)., Results: Cell viability studies, cell uptake observations by confocal microscopy, and uptake quantification by fluorimetry, disclosed clear differences between two formulations, as well as between two types of cell lines. After i.v. injection of the two iodinated nano-emulsions in mice, CT scans provided the quantification of the pharmacokinetics and biodistributions. We finally showed that the size in the nano-emulsions has not a real impact on the pharmacokinetics and biodistributions, but has a strong influence on their toxicity, corroborating the in vitro results., Conclusions: This study shows that the size of the nanocarrier significantly matters, likely due to highly different interactions with cells and tissues. Graphical Abstract A study on the effect of the size of cholecciferol nano-emulsions, on their in vivo becoming, through X-ray imaging modality.

Harpin proteins stimulate hypersensitive response (HR) in plants. However, the mechanism by which HR is regulated is not clear. The role of the auxin, indole-3-acetic acid (IAA), in the control of harpin-stimulated HR was investigated. IAA was used to inhibit HR that was stimulated by purified fusion harpin(Xoo) protein in tobacco. Semi-quantitative PCR and qRT-PCR were employed to detect the expression of HR related genes. IAA at 100 μM reversed harpin-induced HR which was inhibited by 500 μM 2,3,5-triiodobenzoic acid (TIBA). Semi-quantitative PCR and qRT-PCR showed the combined application of 100 μM IAA and harpin protein from Xanthomonas oryzae enhanced the expression of HR marker gene, hsr203J, but weakened the expression of the disease-defense gene, chia5. TIBA also decreased the expression of hsr203J but increased the expression of chia5. Thus, the auxin can reverse harpin(Xoo)-induced HR.

Background: The accumulation of macrophages in inflamed atherosclerotic plaques has long been recognized. In an attempt to develop an imaging agent for detection of vulnerable plaques, we evaluated the feasibility of a liposomal-iodine nanoparticle contrast agent for computed tomography imaging of macrophage-rich atherosclerotic plaques in a mouse model., Methods and Results: Liposomal-iodine formulations varying in particle size and polyethylene glycol coating were fabricated and shown to stably encapsulate the iodine compound. In vitro uptake studies using optical and computed tomography imaging in the RAW 264.7 macrophage cell line identified the formulation that promoted maximal uptake. Dual-energy computed tomography imaging using this formulation in apolipoprotein E-deficient (ApoE(-/-)) mice (n=8) and control C57BL/6 mice (n=6) followed by spectral decomposition of the dual-energy images enabled imaging of the liposomes localized in the plaque. Imaging cytometry confirmed the presence of liposomes in the plaque and their colocalization with a small fraction (≈2%) of the macrophages in the plaque., Conclusions: The results demonstrate the feasibility of imaging macrophage-rich atherosclerotic plaques using a liposomal-iodine nanoparticle contrast agent and dual-energy computed tomography.

Red blood cells demonstrate a unique ability for repeated large deformation. Under the influence of a variety of agents, shapes other than the discocyte--e.g. stomatocytes or echinocytes--can be observed. Some radiographic agents induce shape changes from discocytic to echinocytic cells. Especially the echinocyte formation is associated with a rigidification of the cells bearing the risk of a hindered capillary passage of the echinocytes. The mechanisms leading to the formation of echinocytes are not well understood assuming that the membrane cytoskeleton is a key player. That is why this examination was focused on the participation of components of the membrane cytoskeleton in the formation of echinocytes and the protrusions accompanying the formation of echinocytes. Two radiographic contrast media approved for intra-arterial application were used to study echinocyte formation (Iodixanol320; Iopromide370). In the in vitro study serious changes in the membrane cytoskeleton were only found in those erythrocytes incubated in plasma supplemented with Iopromide370 (30%v/v). The shape of the spectrin net was completely altered; from the more homogeneous distribution--typical of cells in autologous plasma and also of cells in plasma supplemented with Iodixanol320--to a distribution of spectrin concentrated in the membrane-near regions with the appearance of spectrin-actin co-localization. Co-localized spectrin with actin was also found around the membranous roots of protrusions which resemble exocytotic processes. In central parts of the cells there was a pronounced dissociation of spectrin and actin; green coloured condensed spectrin bundles originating from the cell membrane reached up to the root of the protrusions. Separate from this there were also fine long actin fibres passing through the whole cell. The incubation of erythrocytes in plasma supplemented with Iopromide370 induced rounded bubble-like protrusions from the cell membrane containing almost completely long bundles of actin fibres. The examination confirmed earlier studies showing that some radiographic contrast media are able to induce echinocyte formation. Furthermore, subcellular mechanisms were revealed explaining the different effects of Iodixanol in comparison to Iopromide.

Objective: Modern iodinated non-ionic contrast agents (CAs) can be classified based on their molecular structure into monomeric and dimeric CAs and have at comparable iodine concentrations a different viscosity and osmolality. During their renal excretion, CAs are concentrated in the renal tubuli which might enhance the viscosity difference between monomeric and dimeric CAs. The viscosity of a CA might have an underestimated importance for renal safety, as suggested by recent publications. In this study, we investigated the viscosities of CAs at the concentrations expected to be present in renal tubules. This concentration process was simulated in vitro using dialysis. Furthermore, we investigated urine viscosity and urine flow in rodents after administration of several non-ionic monomeric and dimeric CAs., Materials and Methods: To estimate the viscosity of the CAs in vivo, we performed an in vitro dialysis of monomeric and dimeric CAs at various physiological osmolalities of the renal tubulus (290, 400, 500, 700 and 1000 mOsm/kg H2O). Following the dialysis, the iodine concentrations and the viscosities of the CAs were determined. Furthermore, to investigate the concentration process in vivo, we measured the urine viscosity and the urine flow in Han Wister rats after the administration of Iopromide, Iohexol, Ioversol, Iomeprol, Iodixanol, and Iosimenol at comparable iodine concentrations. As a control, saline was injected at the same volume., Results: In vitro dialysis of the dimeric CA increased the iodine concentration and strongly increased the viscosity at all tested osmolalities. In contrast, for the monomeric agents an increase in concentration and viscosity was observed only at 700 as well 1000 mOsm/kg H2O but to a lesser extent. In summary, dialysis strongly enhanced the viscosity differences between the non-ionic monomeric and dimeric CAs. The administration of dimeric CAs leads to a strong increase in urine viscosity; this was not observed for the monomeric CAs. In contrast, a significantly higher urine flow was measured after the administration of the monomeric CAs as compared to the dimeric CAs., Conclusion: We demonstrated that the viscosity differences between monomeric and dimeric CAs are strongly enhanced due to a concentration process of the CAs upon increasing osmolalities, a process which is likely to take place in a similar manner in the tubular system. This result suggests that the viscosity of the dimeric agents increases dramatically in vivo and gives a plausible explanation for measured enhancement of urine viscosity upon dimeric CA administration. On the other hand, the higher osmolality of the monomeric agents causes an osmodiuresis, indicated by a higher urine flow, which leads to a faster elimination of the CAs from the kidney., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

The incubation of erythrocytes (RBC) or endothelial cells (HUVEC) in radiographic contrast media (RCM) could induce morphological alterations of or at the cell membranes, e.g. the generation of echinocytes or the formation of stress fibres coinciding with a massive buckling of HUVEC into the vascular lumen, as was demonstrated in several examinations in the recent years. The apposition or embedding of RCM at or in the cell membranes was discussed as possible causative mechanisms because the embedding of molecules into the internal leaflet of the cell membrane bilayer is expected to bulge the cell membrane to the outside, thus inducing e.g. the generation of echinocytes. The examination presented here is based therefore on high resolution scanning electron microscopy (SEM) analyses if iodine as marker element of RCM molecules can be found near the inside of or in RBC membranes (co-localisation study). Morphological analyses exploited secondary electron images (SE) while the analysis of elements exploited either back scattered electrons (BSE) or energy dispersive X-ray analysis (EDX) or the areal display of elements in high lateral resolution in the Bit-map modus. Even at the highest convenient magnification (1:40,000) it was impossible to detect RBC membrane associated iodine (I) after RBC incubation in RCM (Iodixanol, Iopromide) in vitro. Neither in the birds view on the samples nor looking from the side on the freeze fractured samples carrying the RBC was it possible to detect either the signal cohorts typical of I in the sum spectra or the main Lα1-peak in trace analysis.

Triiodobenzoic acid (TIBA) represents the core structure of most clinically used contrast agents for computed tomography and other X-ray procedures. To construct an intracellular radiopaque contrast agent, TIBA was coupled to various different positively and negatively charged fluorescein iothiocyanate (FITC)-labelled peptides. TIBA coupled to the SV40 T Antigen nuclear localization sequence (NLS) stained 80% of human glioma cells and caused cell death. This occurred with C- or N-terminal binding of TIBA and with the correct or mutant NLS. No cell death and only small numbers of stained cells (below 3 %) were observed after incubation with NLS conjugates lacking TIBA or after incubation with TIBA-conjugates containing a negatively charged polyglutamic acid stretch. TIBA-conjugates containing the Antennapedia-derived cell-penetrating peptide penetratin were only nuclearly taken up when TIBA and FITC were coupled to lysines outside the 16-amino acid peptide sequence. The study shows that intracellular TIBA may have potential as a chemotherapeutic agent rather than a contrast agent.

The crystal structure of the Mycoplasma hyorhinis protein Mh-p37 has been solved and refined to 1.9 A resolution. This is the first de novo structure to be determined using the recently described heavy-atom reagent [Beck et al. (2008), Acta Cryst. D64, 1179-1182] 5-amino-2,4,6-triiodoisophthalic acid (I3C), which contains three I atoms arranged in an equilateral triangle, by SIRAS methods. Data collection was performed in-house at room temperature. SHELXD and SHELXE were used to determine the I-atom positions and phase the native protein and PHENIX AutoBuild software was used to automatically fit the amino-acid sequence to the electron-density map. The structure was refined using SHELX97 to an R(cryst) of 18.6% and an R(free) of 24.0%. Mh-p37 is an alpha/beta protein with two well defined domains which are separated by a deep cleft. An unanticipated ligand bound in the center of the molecule at the base of the cleft has been modeled as thiamine pyrophosphate or vitamin B(1). Retrospective attempts to solve the crystal structure by Patterson search methods using either isomorphous or anomalous differences failed. Additionally, attempts to use proteins with the highest structural homology in the Protein Data Bank to phase the data by molecular replacement were unsuccessful, most likely in hindsight because of their poor structural agreement. Therefore, the I3C reagent offers an alternative, quick and inexpensive method for in-house phasing of de novo structures where other methods may not be successful.

Obtaining phase information for the solution of macromolecular structures is still one of the bottlenecks in X-ray crystallography. 5-Amino-2,4,6-triiodoisophthalic acid (I3C), in which three covalently bound iodines form an equilateral triangle, was incorporated into proteins in order to obtain phases by single-wavelength anomalous dispersion (SAD). An improved binding capability compared with simple heavy-metal ions, ready availability, improved recognition of potential heavy-atom sites and low toxicity make I3C particularly suitable for experimental phasing.

By interacting with the cytoplasmic tail of a Golgi-processed form of transforming growth factor-alpha (TGFalpha), Naked2 coats TGFalpha-containing exocytic vesicles and directs them to the basolateral corner of polarized epithelial cells where the vesicles dock and fuse in a Naked2 myristoylation-dependent manner. These TGFalpha-containing Naked2-associated vesicles are not directed to the subapical Sec6/8 exocyst complex as has been reported for other basolateral cargo, and thus they appear to represent a distinct set of basolaterally targeted vesicles. To identify constituents of these vesicles, we exploited our finding that myristoylation-deficient Naked2 G2A vesicles are unable to fuse at the plasma membrane. Isolation of a population of myristoylation-deficient, green fluorescent protein-tagged G2A Naked2-associated vesicles was achieved by biochemical enrichment followed by flow cytometric fluorescence-activated vesicle sorting. The protein content of these plasma membrane de-enriched, flow-sorted fluorescent G2A Naked2 vesicles was determined by LC/LC-MS/MS analysis. Three independent isolations were performed, and 389 proteins were found in all three sets of G2A Naked2 vesicles. Rab10 and myosin IIA were identified as core machinery, and Na(+)/K(+)-ATPase alpha1 was identified as an additional cargo within these vesicles. As an initial validation step, we confirmed their presence and that of three additional proteins tested (annexin A1, annexin A2, and IQGAP1) in wild-type Naked2 vesicles. To our knowledge, this is the first large scale protein characterization of a population of basolaterally targeted exocytic vesicles and supports the use of fluorescence-activated vesicle sorting as a useful tool for isolation of cellular organelles for comprehensive proteomics analysis.

Iodinated X-ray contrast media have been detected in hospital effluent, sewage treatment plant effluent, rivers and groundwater aquifers. No process has been developed to remove triiodinated aromatic molecules. In this paper, we present a biological sequential process using an anaerobic fixed-bed reactor coupled in series with an aerobic fixed-bed reactor for degrading 5-amino-2,4,6-triiodoisophthalic acid (ATIA), the core structure of a X-ray contrast media family. The results obtained showed that the coupled reactor eliminated up to 870+/-44 mg of carbon L(-1) day(-1), with a molar ethanol/ATIA ratio of 4 in the feeding medium. The anaerobic reactor (ANR) undertook the majority of the deiodination of the aromatic nucleus and had a maximum deiodination rate of 23.4+/-0.06 mM day(-1). The aerobic reactor (AER) mineralized ATIA and was also able to eliminate its metabolites. This study suggests that the mineralization of ATIA can be achieved efficiently in a coupled anaerobic-aerobic bioreactor.

Iron regulatory proteins 1 and 2 (IRP1, IRP2) are key determinants of uptake and storage of iron by the liver, and are responsive to oxidative stress and hypoxia potentially at the level of both protein concentration and mRNA-binding activity. We examined the effect of hypoxia (1% O(2)) on IRP1 and IRP2 levels (Western blots) and mRNA-binding activity (gel shift assays) in human hepatoma HepG2 cells, and compared them with HEK 293 cells, a renal cell line known to respond to hypoxia. Total IRP binding to an iron responsive element (IRE) mRNA probe was increased several fold by hypoxia in HEK 293 cells, maximally at 4-8 h. An earlier and more modest increase (1.5- to 2-fold, peaking at 2 h and then declining) was seen in HepG2 cells. In both cell lines, IRP1 made a greater contribution to IRE-binding activity than IRP2. IRP1 protein levels were increased slightly by hypoxia in HEK 293 but not in HepG2 cells. IRP1 was distributed between cytosolic and membrane-bound fractions, and in both cells hypoxia increased both the amount and IRE-binding activity of the membrane-associated IRP1 fraction. Further density gradient fractionation of HepG2 membranes revealed that hypoxia caused an increase in total membrane IRP1, with a shift in the membrane-bound fraction from Golgi to an endoplasmic reticulum (ER)-enriched fraction. Translocation of IRP to the ER has previously been shown to stabilize transferrin receptor mRNA, thus increasing iron availability to the cell. Iron depletion with deferoxamine also caused an increase in ER-associated IRP1. Phorbol ester caused serine phosphorylation of IRP1 and increased its association with the ER. The calcium ionophore ionomycin likewise increased ER-associated IRP1, without affecting total IRE-binding activity. We conclude that IRP1 is translocated to the ER by multiple signals in HepG2 cells, including hypoxia, thereby facilitating its role in regulation of hepatic gene expression.

PARsylation [poly(ADP-ribosyl)ation] of proteins is implicated in the regulation of diverse physiological processes. Tankyrase is a molecular scaffold with this catalytic activity and has been proposed as a regulator of vesicular trafficking on the basis, in part, of its Golgi localization in non-polarized cells. Little is known about tankyrase localization in polarized epithelial cells. Using MDCK (Madin-Darby canine kidney) cells as a model, we found that E-cadherin-mediated intercellular adhesion recruits tankyrase from the cytoplasm to the lateral membrane (including the tight junction), where it stably associates with detergent-insoluble structures. This recruitment is mostly completed within 8 h of calcium-induced formation of cell-cell contact. Conversely, when intercellular adhesion is disrupted by calcium deprivation, tankyrase returns from the lateral membrane to the cytoplasm and becomes more soluble in detergents. The PARsylating activity of tankyrase promotes its dissociation from the lateral membrane as well as its ubiquitination and proteasome-mediated degradation, resulting in an apparent protein half-life of approximately 2 h. Inhibition of tankyrase autoPARsylation using H2O2-induced NAD+ depletion or PJ34 [N-(6-oxo-5,6-dihydrophenanthridin-2-yl)-N,N-dimethylacetamide hydrochloride] treatment results in tankyrase stabilization and accumulation at the lateral membrane. By contrast, stabilization through proteasome inhibition results in tankyrase accumulation in the cytoplasm. These data suggest that cell-cell contact promotes tankyrase association with the lateral membrane, whereas PARsylating activity promotes translocation to the cytosol, which is followed by ubiquitination and proteasome-mediated degradation. Since the lateral membrane is a sorting station that ensures domain-specific delivery of basolateral membrane proteins, the regulated tankyrase recruitment to this site is consistent with a role in polarized protein targeting in epithelial cells.

Background: Loosening is a major complication in prosthesis surgery. To stabilize loosened orthopedic implants, the interface tissue surrounding the implant must be removed. As an alternative to manual removal, we explored the possibility of removing the tissue by gene-directed enzyme prodrug therapy. In the current study we investigated whether interface cells can be transduced by an HAdV-5 vector carrying the E.coli-derived nitroreductase gene and sensitized to the prodrug CB1954., Methods: The gene transfer efficiency into cultures of diploid human interface cells was tested by exposing these cells to various concentrations of Ad.CMV.LacZ. Subsequently, we studied the susceptibility of cells to the NTR/CB1954 combination., Results: X-gal staining of the Ad.CMV.LacZ-transduced cell cultures revealed that, at 200 plaque-forming units (pfu)/cell, 74% of the cells expressed the LacZ gene. Infection with an NTR construct in interface cell lines resulted in a 60-fold sensitization to the prodrug CB1954. In addition we observed that iotrolan (Isovist) contrast medium had no effect on viability of the cells. However, the presence of the contrast medium completely inhibited adenovirus-mediated gene transfer., Conclusions: From these data we conclude that HAdV-5-based vectors carrying nitroreductase can be used to sensitize interface tissue. Instead of contrast medium the clinical protocol will use an alternative visualization procedure., (Copyright (c) 2005 John Wiley & Sons, Ltd.)

Cisplatin is a chemotherapeutic agent commonly used in the treatment of a wide variety of malignant tumors. Resistance to cisplatin represents a major obstacle to effective cancer therapy because clinically significant levels of resistance quickly emerge after treatment. Based on previous studies indicating abnormal plasma membrane protein trafficking in cisplatin-resistant (CP-r) cells, Fluorescence (Alexa Fluor)-labeled cisplatin was used to determine whether this defect altered the trafficking and localization of cisplatin by comparing drug sensitive KB-3-1 and KB-CP-r cells. Alexa Fluor-cisplatin was readily internalized and localized throughout the KB-3-1 cells, but overall fluorescence decreased in KB-CP-r cells, as detected by flow cytometry (FACS) and confocal microscopy. Only punctate cytoplasmic staining was observed in KB-CP-r cells with less fluorescence observed in the nucleus. Colocalization experiments with a Golgi-selective stain indicate the involvement of Golgi-like vesicles in initial intracellular processing of Alexa Fluor conjugated cisplatin complexes. As detected using an antibody to Alexa Fluor-cisplatin, cisplatin complex-binding proteins (CCBPs) were reduced in membrane fractions of single-step cisplatin-resistant KB-CP.5 cells, and increased in the cytoplasm of KB-CP.5 cells compared to KB-3-1 cells. CCBPs localized to lower density fractions in KB-CP.5 cells than in KB-3-1 cells as determined by iodixanol gradient centrifugation. In summary, inappropriate trafficking of CCBPs might explain resistance to cisplatin in cultured cancer cells, presumably because membrane binding proteins for cisplatin are not properly located on the cell surface in these cells, but are instead trapped in low density vesicles within the cytoplasm., (2004 Wiley-Liss, Inc.)

5-Amino-2,4,6-triiodoisophthalic acid (ATIA), both a precursor and a degradative intermediate of triiodinated contrast media, was anaerobically converted by sludge from a wastewater treatment plant. ATIA conversion took place only when an electron donor such as ethanol was added. A stable mixed culture was established by transfer to a defined synthetic mineral medium with ATIA and ethanol. It could be maintained for 1 year when the sulfate concentration was kept below 30 microM. Transient appearance of 5-amino-2,4-diiodoisophthalic acid, iodide release (2.7 mol iodide/mol ATIA) and accumulation of 5-aminoisophthalic acid indicated that ATIA was reductively dehalogenated. The enriched mixed culture also dehalogenated ATIA derivatives but deiodination remained incomplete. ATIA was the sole terminal electron acceptor used by the mixed culture during deiodination. The ratio of electrons transferred to ATIA, 0.83, was consistent with a respiratory metabolism. Formate, acetate, lactate, butyrate and hydrogen were also used as electron donors. Deiodination was inhibited by a headspace of air or by addition of nitrate, sulfite or thiosulfate. The reaction was 2.6 times slower with sulfate than without.

Auxin distribution during embryogenesis and seed germination were studied with transgenic Arabidopsis plants expressing GUS gene driven by a synthetic DR5 promoter, an auxin responsive promoter. The results showed that GUS activity is higher in ends of hypophysis and cotyledon primordia of heart-, torpedo- and cotyledon-stage embryos, leaf tip area, lateral root primordia, root apex and cotyledon of young seedlings. And GUS accumulated in root apex of the seedlings grown on auxin transport inhibitor containing media. All these suggested that above-mentioned part of the organs and tissues have a higher level of auxin, and auxin polar transport inhibitor could cause the accumulation of auxin in root apex. And auxin transport inhibitor also resulted in aberration of Arabidopsis leaf pattern formation, root gravitropism and elongation.

Rationale and Objectives: Most radiographic contrast media (CM) are hyperosmotic and pose an osmotic threat to cells they are in contact with. To study these effects at the cellular level, cell volume regulatory mechanisms were observed in proximal renal tubules following exposure to the CM iohexol, ioxaglate, and iodixanol., Materials and Methods: Isolated renal tubules from trout (Salmo trutta) were exposed to 5% vol/vol iohexol (326 mOsm), ioxaglate (314 mOsm), or iodixanol (300 mOsm) or mannitol (to achieve the same osmolalities), and cell volume changes were observed videometrically., Results: Iohexol and ioxaglate solutions induced a rapid shrinkage (12%-13%) not followed by cell volume regulation. Without CM (same osmolality), the cells shrank 11% but then showed a 77%-88% volume recovery. This reswelling was inhibited by 55% with the Na+, K+, Cl- symporter inhibitor bumetanide (50 micromol/L). Iodixanol did not significantly affect cell volume. Tubules preincubated with CM or mannitol were then stimulated with a hypoosmotic Ringer solution (160 mOsm) resulting in a 26%-36% cellular volume increase. Compared with results of experiments without mannitol and CM, preexposure to iohexol or ioxaglate almost completely inhibited the expected regulatory shrinkage phase, while previous exposure to hyperosmotic solutions with mannitol reduced the shrinkage response by 40%-53%., Conclusion: In this system, the hyperosmotic iohexol and ioxaglate cause cell shrinkage followed by an impaired cell volume regulatory response. Exposure to these two CM also inhibits cell volume regulation on hypoosmotic stimulation. The isosmotic iodixanol has no such effects. These changes appear to some extent to be a result of the CM's degree of hyperosmolality, but this property alone does not explain these findings.

The coronavirus replicase gene (gene 1) is translated into two co-amino-terminal polyproteins that are proteolytically processed to yield more than 15 mature proteins. Several gene 1 proteins have been shown to localize at sites of viral RNA synthesis in the infected cell cytoplasm, notably on late endosomes at early times of infection. However, both immunofluorescence and electron microscopic studies have also detected gene 1 proteins at sites distinct from the putative sites of viral RNA synthesis or virus assembly. In this study, mouse hepatitis virus (MHV)-infected cells were fractionated and analyzed to determine if gene 1 proteins segregated to more than one membrane population. Following differential centrifugation of lysates of MHV-infected DBT cells, gene 1 proteins as well as the structural N and M proteins were detected almost exclusively in a high-speed small membrane pellet. Following fractionation of the small membrane pellet on an iodixanol density gradient, the gene 1 proteins p28 and helicase cofractionated with dense membranes (1.12 to 1.13 g/ml) that also contained peak concentrations of N. In contrast, p65 and p1a-22 were detected in a distinct population of less dense membranes (1.05 to 1.09 g/ml). Viral RNA was detected in membrane fractions containing helicase, p28, and N but not in the fractions containing p65 and p1a-22. LAMP-1, a marker for late endosomes and lysosomes, was detected in both membrane populations. These results demonstrate that multiple gene 1 proteins segregate into two biochemically distinct but tightly associated membrane populations and that only one of these populations appears to be a site for viral RNA synthesis. The results further suggest that p28 is a component of the viral replication complex whereas the gene 1 proteins p1a-22 and p65 may serve roles during infection that are distinct from viral RNA transcription or replication.

Background: During the production process of the X-ray contrast agent iodixanol the drug substance may be exposed to acid, base, air, heat and daylight, conditions that may cause decomposition products., Objective: To investigate the chemical stability of iodixanol under accelerating conditions., Method: Chemometrical stability studies were undertaken to investigate the effect of acid and base on the contrast agent's stability., Results: Cleavage of the central bridge in iodixanol occurred under ultraviolet irradiation via a Norrish Type-II reaction. Basic conditions (pH 14) combined with heat (60 degrees C) initiated a cyclization reaction. Less than 1% iodixanol decomposed in solution heated to 140 degrees C for 2 days or under both basic conditions (pH 11, 20 degrees C, 5 days) and acidic conditions (pH 0.4, 80 degrees C, 5 days) or under oxygen atmosphere (100 degrees C, 3 days)., Conclusion: Even under highly acidic and basic conditions, iodixanol is stable.

Conventional methods for rAAV purification that are based on cesium chloride ultracentrifugation have often produced vector preparations of variable quality and resulted in significant loss of particle infectivity. We report here several novel purification strategies that involve the use of non-ionic iodixanol gradients followed by ion exchange or heparin affinity chromatography by either conventional or HPLC columns. These methods result in more than 50% recovery of rAAV from a crude lysate and routinely produce vector that is more than 99% pure. More importantly, the new purification procedures consistently produce rAAV stocks with particle-to-infectivity ratios of less than 100, which is significantly better than conventional methods. The new protocol increases the overall yield of infectious rAAV by at least 10-fold and allows for the complete purification of rAAV in 1 working day. Several of these methods should also be useful for large-scale production.

Iodixanol is a new, nonionic, iodinated density gradient medium which has an advantage over other similar media in that it rapidly forms self-generated gradients in vertical or near-vertical rotors. Endocytosis of 99mTc-labeled neogalactosyl albumin (99mTc-NGA), a synthetic ligand for the asialoglycoprotein receptor, was studied by administering the ligand as a short pulse to perfused rat livers operating under single-pass conditions. Intracellular processing was arrested at various times after the pulse and the resultant homogenate cleared of nuclei and heavy mitochondria by centrifugation at 3000 g for 10 min. After adjustment to 12.5% (w/v) iodixanol, the 3000 g supernatants were centrifuged at 350,000 g for 60 min to form the gradients in which early, clathrin-containing vesicles, low-density endosomes, and lysosomes were well-resolved. 99mTc-NGA bound to the sinusoidal membrane could be partially resolved from clathrin-containing vesicles by inclusion of 1 mM CaCl2 in the homogenization and gradient buffers. Two populations of early clathrin-containing vesicles could be resolved by rate-zonal centrifugation in preformed iodixanol gradients. Thus, iodixanol is an excellent density gradient medium for the rapid and efficient resolution of endosome compartments.

Portions of the shoot system from young light-grown pea (Pisum sativum L.) seedlings were excised and circumnutation studied using time-lapse cinematography. Removal of the youngest leaf or shoot tip as well as ringing the stem with 20 mM triiodobenzoic acid severely restricted circumnutation. Treating the stump of the excised leaf with lanolin containing 10(-4) M indole-3-acetic acid or replacing the leaf with an artificial aluminum leaf both partially restored circumnutation. When the leaf was replaced with both auxin and an artificial leaf circumnutation continued at approximately the rate of the intact plant. This graphically shows the involvement of both auxin and gravitropism in circumnutation.

Microsomal chitinase from yeast and hyphal cells of Candida albicans was activated endogenously by incubation at 30 degrees C and exogenously by trypsin. The putative activating factor of yeast cells was separated from chitinase activity by fractionation of lysed protoplasts on an Iodixanol density gradient. The vacuole fraction contained no significant chitinase activity, but was enriched in chitinase activating factor. Activity of microsomal chitinase increased upon incubation with this, but no other gradient factor. Results suggest that the regulatory system governing microsomal chitinase activity, like that governing chitin synthase, involves a 'vacuolar' activating factor in Candida albicans.

The aim of this study was to compare the in vitro effects of different classes of contrast media on both the blood coagulation system and on platelet function. Global tests (APTT, TT) and FpA and F1 + 2 generation measurements showed that ioxaglate (ionic dimer) presents the highest anticoagulant potential. The anticoagulant effects of nonionic agents were less marked, iodixanol (nonionic dimer) being significantly less anticoagulant than iohexol (nonionic monomer). Major platelet activation was observed with release of PF4, serotonin and PDGF-AB when iohexol was incubated for 1 min in whole blood. Iodixanol showed no effect over the same period, while moderate platelet activation was observed after 30 min. Under the same experimental conditions, ioxaglate had no effect on platelets even after incubation for 30 min, whereas activation was observed with 9 g/l saline control at this time. Prevention of thrombin formation and platelet activation is only achieved with ioxaglate, the ionic dimer. These findings may be clinically important in the thrombotic environment of radiological procedures and may explain the increased thrombotic risks observed with nonionic agents in interventional procedures.

Background: Intestinal ischaemia may be difficult to recognize in the early stages. Increased urinary recovery of water-soluble contrast medium during and intestinal follow-through has been suggested as a sign of bowel ischaemia., Methods: Urinary excretion of the isosmolar water-soluble X-ray contrast medium iodixanol was measured after instillation via an orogastric tube in 56 rats with occlusion of the mesenteric blood vessels., Results: Mesenteric venous occlusion caused only minor histologic alterations of the mucosa. High-performance liquid chromatography (HPLC) and X-ray fluorescence analysis measured urinary iodixanol concentrations 10 and 13 times higher than in the groups with mesenteric arterial occlusion than in controls (p < 0.001), and 3 and 4 times higher than in the group with venous occlusion (p < or = 0.05). Correlation between HPLC and X-ray fluorescence measurements of contrast medium in urine was strong (r = 0.98)., Conclusion: Measuring urinary contrast medium levels during intestinal follow-through may aid in distinguishing bowel ischaemia following mesenteric arterial occlusion from mesenteric venous occlusion and from the normal bowel.

The binding of warfarin, a series of non-steroidal anti-inflammatory drugs and a series of benzodiazepines to rat serum albumin (RatSA) and rabbit serum albumin (RabSA) was compared with their binding to human serum albumin (HSA) using high-performance liquid chromatography on stationary phases based on immobilized albumins. The effect of the addition to the mobile phase of compounds known to bind to HSA at site I (phenylbutazone) or at site II (R- and S-ibuprofen) or at both sites (2,3,5-triiodobenzoic acid) was investigated on all three proteins. The results indicated that for the chiral compounds studied, the stereoselectivity of drug binding was much lower on RatSA than on HSA. On RatSA and RabSA, the benzodiazepine site was not a major binding site for R- and S-ibuprofen. The results indicated the existence of two binding sites for R and S warfarin on RatSA and probably on RabSA. On RatSA, one site is the major stereoselective site and is the major binding site of phenylbutazone and piroxicam. The other one is a major binding site for R- and S-ibuprofen and R- and S-ketoprofen.

Twenty-eight consecutive patients undergoing cervical myelography were examined with either iohexol (14) or iotrolan (14). Just before the myelography a cranial CT was performed and control CT (3-5 slices) examinations were performed three, six, 24 and 48 hours afterwards. In all 28 patients CT showed intracranial contrast medium distribution after cervical myelography. The contrast medium distributed mainly in the subarachnoid space, first to the basal cisterns and the insular fissures, and to the 4th ventricle. The densities in the subarachnoid spaces were significantly higher after iotrolan than iohexol in the basal cisterns three and six hours after myelography, and in the 4th ventricle. The subcortical density was still increasing 48 hours after iotrolanmyelography while the subcortical density reached the maximum 24 hours after iohexolmyelography. Following cervical myelography the contrast media iohexol and iotrolan distribute intracranially and iotrolan seems to be eliminated more slowly than iohexol.

The iodine-specific detection techniques X-ray fluorescence spectrometry, neutron activation analysis and radiochemical detections of (125)I-labelled substance are well suited for quantification of iodixanol in biological samples. The limit of detection is 60 microgram iodixanol/ml for X-ray fluorecence analysis and 1 to 10 microgram iodixanol/ml for neutron activation analysis. Reversed-phase high-performance liquid chromatography (HPLC) has been employed when selective determination of iodixanol was needed for identificational purposes or when quantification of very small amounts of iodixanol was essential. An optimized HPLC method for quantification of iodixanol in rat serum and urine is presented. The limit of detection for this method is 0.20 microgram iodixanol/ml for rat serum and 3.0 microgram iodixanol/ml for rat urine. When samples were analyzed by HPLC and thin layer chromatography, no metabolites of iodixanol were observed in rat, monkey or human urine, or in rat kidney and bile. Studies with equilibrium dialysis and HPLC determination of iodixanol showed no protein binding of the contrast agent in human plasma; the 95% confidence interval for the result was 0.0+/-2.1%.

During coronary angiography the exchange of blood with a contrast medium solution causes a period of hypoxia. To investigate whether oxygen saturation of the contrast medium could be beneficial, low osmolar contrast media were infused without and with oxygen saturation into the coronary arteries of the isolated rabbit heart. Iohexol (150-300 mg I/ml, without NaCl or with 20-30 mM NaCl), iodixanol (320 mg I/ml, contains 24 mM NaCl) and ioxaglate (160 mg I/ml, contains 75 mM Na+) were infused without and with oxygen saturation. The decrease in contractile force (CF) of the heart, from the contrast medium solutions, was reduced when the solutions were saturated with oxygen. Oxygen saturation of iohexol (350 mg I/ml, without or with 10 mM NaCl) did not change the frequency of ventricular fibrillations (VF). Low osmolar contrast media, when saturated with oxygen, thus caused a reduced decrease in CF without changing the frequency of VF. This might be beneficial in clinical cardioangiography by reducing the adverse effects from the media.

After suboccipital injection of Iotrol and Iopamidol labelled with iodine 125 in rabbits, we measured residual radioactivity in the whole brain and optical density on autoradiographs of brain sections obtained 2, 8 and 24 h after injection. Residual radioactivity is higher with Iotrol than with Iopamidol after 8 h and 24 h. At densitometry, while the penetration of the cortex is the same with both media at 2 h (although subcortical passage of Iotrol is greater), by 8 h the concentration of Iopamidol is twice that of Iotrol, and at 24 h it is three times as high. A similar pattern was seen in the subcortical region. These densitometric findings are in agreement with previous electrophysiological studies, in which changes were less severe and more transient with Iotrol than with Iohexol. There is nevertheless an apparent lack of agreement between the studies of radioactivity and the electrical findings. The lower neurotoxicity of Iotrol may be explained by: a longer half-life in the subarachnoid space; its larger molecules, which inhibit diffusion in the extracellular fluid, and its more hydrophilic nature, which reduces intracellular penetration.

Mechanisms involved in the biliary excretion of organic anions were investigated in hemoglobin-free perfused rat liver using iotroxic acid as a test substance. The process of biliary excretion in this system can be separated into three elemental processes, i.e. 1) diffusion into hepatocytes, 2) protein-binding with intracellular protein (accumulation) and 3) active transport into bile. Elimination of iotroxic acid from the perfusate into the hepatocytes followed first-order kinetics, indicating the process to be that of passive diffusion. Though the biliary excretion occurred rather rapidly, the amount of iotroxic acid in the hepatocytes increased with increases in the initial concentration in the perfusate and approached a maximal amount of ca. 2.8 mu moles/g wet weight of liver. The maximal values observed for the biliary concentration and the rate of biliary transport were 20-24 mM and 38-48 nmoles/min . g liver, respectively. Bromsulphalein inhibited the diffusion of iotroxic acid into the hepatocytes whereas accumulation of iopodic acid in the hepatocytes produced an inhibition of diffusion into the hepatocytes and transport into the bile. Dexamethasone-21-sulfate (DXMS) was transported rapidly into the bile, but in the presence of iotroxic or iopodic acids, excretion of DXMS into the bile was inhibited, while diffusion into the hepatocytes was inhibited only by iopodic acid. The competition observed with those substances demonstrates the presence of a common mechanism for the biliary transport of organic anions in the liver.

Iopromide (Schering, Berlin) is a new nonionic, monomeric contrast medium containing three different substituents on the triiodinated benzene ring. Iopromide exhibits low osmolality and viscosity in aqueous solutions of high concentrations. It has been shown to have a remarkably low intravenous toxicity in mice and rats. Neural tolerance was found to be equal to or better than that of metrizamide when injected in rats intracisternally and intracerebrally, respectively. The effects of iopromide after selective peripheral and cerebral arterial injections in rats were demonstrated to be very moderate at high dosages. The interaction of iopromide with proteins and membranes was found to be considerably low due to its hydrophilicity. Excretion of iopromide is fast and predominantly by the renal route. On the basis of the preclinical profile iopromide is a very promising contrast agent, being most suitable for all angiographic indications, including digital subtraction angiography, urography, and computed tomography.

The excretory behavior of nine nephrotropic contrast agents with varying physicochemical properties such as charge, lipophilicity, and molecular size was investigated. Renal clearance in comparison with inulin was determined by means of the continuous infusion method. Each contrast agent was infused at three dose levels in four to six rabbits. The investigations show that tubular transportation in proportion to glomerular filtration decreases with increasing dosages of all the contrast agents. Thus, with the highest concentration in plasma all contrast agents are eliminated at more or less the glomerular filtration rate (GFR). After administration of the low dosages the following differences are found: 1) Net tubular secretion increases for the monomeric contrast agent acids with increasing lipophilicity, in the order diatrizoate congruent to iothalamate less than iodamide less than acetrizoate. 2) The clearance studies do not reveal any tubular secretion or reabsorption for a hydrophilic cationic contrast agent. 3) The nonionic contrast agents do not show net secretion. The more lipophilic they are, the more they are reabsorbed. 4) Two dimeric contrast agents also do not reveal any tubular secretion. They seem to be reabsorbed more than monomers with the same charge.

Pharmacokinetical properties of eight triiodobenzene derivatives, X-ray contrast agents, were studied in the hemoglobin-free perfused rat liver with emphasis on the structural relation to biliary transport. With chemical modification of the basic structure, these agents showed different characteristics in the processes of diffusion into hepatocytes, accumulation in the cells and active transport into the bile, and were separated into four groups; [I]: Iotroxic acid (1), Iodipamic acid (2), Iodoxamic acid (3), and Ioglycamic acid (4) which showed faster rates of diffusion into hepatocytes [(1) greater than or equal to (2) greater than (3) greater (4)] and also of biliary excretion [(1) greater than (2) greater than (4) greater than (3)], [II]: Diatrizoic acid and Metrizamide showed poor diffusion and biliary excretion, [III]: Iopodic acid showed the highest permeability into and accumulation in hepatocytes with little biliary excretion, [IV]: ZK73 215 was slowly transported into the bile, yet, showed little permeation through the cell membrane. Characteristics of (1), (2) and (3) observed in the perfused liver were, in principle, confirmed in the pharmacokinetical profile observed in vivo. However, the fast diffusion of (2) into the hepatocytes appears to be hampered by high binding ability with serum proteins, whereas the relatively poor profile of the biliary excretion of (3) was improved by its low protein-binding in blood in vivo. Superiority of (1) as a cholangiographic agent was demonstrated by the fast biliary excretion in both the case of experimental systems and moderate protein-binding.

The absorption of the nonionic contrast medium iohexol, the clearance tracer 51Cr-ethylenediaminetetraacetic acid, and the blood-pool marker 125I-human serum albumin was studied after subarachnoid and subdural injection in rabbits. Subdural deposition of the contrast medium and 51Cr-ethylenediaminetetraacetic acid resulted in a faster absorption rate and higher achieved blood levels than a subarachnoid injection of the two substances, where a slow absorption to lower blood concentrations was observed. No significant differences in absorption rate could be shown after subdural and subarachnoid administration of iodine-labelled albumin. The excretion of iohexol was observed for 1 week after the intrathecal injection. For both the subdural and subarachnoid depositions, about 83% of the injected iohexol was found in urine within 24 hr after injection. The total recovery of iohexol after 1 week was 96% (range, 87%-101%).

The biotransformation of the 131I-labeled cholegraphic media ioglycamic acid, iodoxamic acid and iotroxic acid in man is investigated. Plasma, urine and fistular bile were analyzed for unchanged and metabolized constituents of the administered substances using thin layer chromatography. No metabolites were found in plasma, but up to two were found in urine in addition to unchanged contrast media (a total of 50% of the total elimination in 24 hr. urine). A metabolite was only found in the fistular bile after the injection of iotroxic acid.

An open cross-over investigation of intravenous digital subtraction angiography of carotid arteries was carried out to compare image quality, side effects and pulmonary circulation time of iohexol and meglumine-Na-Ca metrizoate. Successive injections of the two contrast media were given under identical conditions. A significantly higher frequency of artifacts from swallowing and motion was noted after metrizoate injections. A lower frequency of subjective and objective side effects was found following iohexol injections.

The diffusion of water-soluble contrast media (CM) into the extracellular space of the central nervous system following injection into the subarachnoid space has previously been shown. As a result of this, water-soluble CM will come in direct contact with the neurons and may interfere with their normal function. The toxic effects would thus be a result both of the molecular properties of the CM as well as the local tissue concentration. The neuronal tissue uptake and clearance of metrizamide in rabbits following lumbar myelography was described in a previous study by our group. This study indicated some retention of metrizamide in the spinal cord probably as a result of binding of the CM to the cell membrane. The mechanism for this has not yet been shown although it may relate to the binding of metrizamide via its 2-deoxy-D-glucose (2-DG) portion and the specific glucose membrane carrier. The present investigation was performed to evaluate the diffusion kinetics of a new non-ionic CM. With iohexol, which lacks a 2-DG component in its molecule a direct relationship between the neural tissue and CSF concentration was found which seems to follow a simple diffusion model. Since iohexol shows no sign of entrapment in the tissue, the contact time for neurons will be shorter than that seen with metrizamide assuming that their rate of drainage from the CSF is identical.

The biliary and urinary excretion and the choleretic effect of ioglycamide were studied in unanesthetized bile fistula dogs using stepwise increasing infusion rates to obtain multiple steady states. The results are compared with data from previously reported experiments in the same animals using iodoxamate and iodipamide. The rate of biliary excretion and the choleretic effect of ioglycamide are similar to those of iodipamide and iodoxamate. Like iodipamide and iodoxamate, the relation between infusion rate or plasma concentration and biliary excretion or concentration of ioglycamide are hyperbolic and can be fitted to saturation kinetics. Quantitatively, the excretion of ioglycamide and iodipamide are virtually identical. However, for any equimolar infusion rate or plasma concentration, more iodoxamate than ioglycamide is excreted in the bile. Despite the greater biliary excretion of iodoxamate, the maximum biliary concentration of ioglycamide, iodipamide, and iodoxamate is the same at low basal bile flow because the choleretic effects of the three compounds are equal. The data suggest that, theoretically, with any equimolar dose ioglycamide will be identical to iodipamide as a contrast material for intravenous cholangiography, but that iodoxamate may be superior to ioglycamide because more iodoxamate is excreted in the bile. This advantage of iodoxamate might become apparent clinically in patients with high basal bile flow or if smaller doses of the contrast material are used. However, at the presently recommended doses of the two compounds, it is unlikely that the use of ioglycamide for intravenous cholangiography will be any different than iodoxamate.

Iodipamide and iodoxamate were compared in equimolar clinical dosages in five cholecystectomized chronic bile fistula dogs in which hepatic dysfunction was produced by oral administration of a total dose of 480 and 960 microliters dimethylnitrosamine (DMNA), respectively. After both DMNA dosages, the peak biliary excretion rate for iodoxamate was significantly higher than for iodipamide (p less than 0.01). The peak bile iodine concentration was not significantly different for the two agents (480 microliter DMNA: p less than 0.1; 960 microliter DMNA: p = 0.07). On the basis of this investigation, it is suggested that iodoxamate should not significantly improve the opacification of the biliary system in patients with hepatic dysfunction.

The meglumine salts of iodoxamic and iotroxamic acids are recently developed intravenous cholangiographic media. In several studies these two media have been shown to be significantly better than meglumine iodipamide and meglumine ioglycamate for opacification of the biliary tree and incidence of adverse effects. As part of a multi-centre double-blind trial 100 patients were given iodoxamate or iotroxamate. Comparisons of opacification, side effects and renal excretion of contrast were made. The results showed no statistically significant difference in biliary tree opacification; more frequent renal excretion of contrast with iodoxamate; and contrary to previous reports a slightly higher incidence of side effects with iotroxamate.

A double blind comparison between Ioglycamid (Bilivistan) and the new I-V cholegraphic medium Iotroxamid (proposed trade name Chologram) is reported. Chologram produces better pictures and it is better tolerated. Pharmaco-kinetic data are published for the first time.