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Two retinol derivatives, 4-[(131I)-4-iodobenzoyloxy]retinol propionate and 4-[(131I)-3-iodobenzylcarbamoyl] retinol propionate, were synthesized and their biodistribution in rats was studied in vivo by the whole body scintigraphy. [ABSTRACT FROM AUTHOR]

New (radio)halogen derivatives of 1-allylterguride have been prepared by method of destannylation-halogenation. 1-Alylterguride shows relatively high binding affinity, which can be used in the case of its radiolabeled derivatives with imaging methods like PET or SPET in studies of properties of receptor's binding places and ligand affinity. The (radio)halogenation was performed via organotin precursors: 1-tributylstannyl-3-chlorprop-1-ene and 2-tributylstannyl-3-chloroprop-1-ene, which were prepared from appropriate alcohols. Linkers of the tin group were used for alkylation of N1 of terguride both under microwave irradiation and under conventional heating. In the last step (destannylation-halogenation), fluoro-, bromo- and iododerivatives as well as 125I iodo- and 82Br bromoderivatives of 1-allylterguride were obtained. [ABSTRACT FROM AUTHOR]

Abstract: The short-lived (12.7h half-life) 64Cu radioisotope is both a β + and a β − emitter. This property makes 64Cu a promising candidate for novel medical applications, since it can be used simultaneously for therapeutic application of radiolabelled biomolecules and for diagnosis with PET. Following previous work on 64Cu production by deuteron irradiation of natural zinc, we report here the production of this radioisotope by deuteron irradiation of enriched 64Zn. In addition, yields of other radioisotopes such as 61Cu, 67Cu, 65Zn, 69mZn, 66Ga and 67Ga, which were co-produced in this process, were also measured. The evaporation code ALICE-91 and the transport code SRIM 2003 were used to determine the excitation functions and the stopping power, respectively. All the nuclear reactions yielding the above-mentioned radioisotopes were taken into account in the calculations both for the natural and enriched Zn targets. The experimental and calculated yields were shown to be in reasonable agreement. The work was carried out at the Scanditronix MC-40 Cyclotron of the Institute for Health and Consumer Protection of the Joint Research Centre of the European Commission (Ispra site, Italy). The irradiations were carried out with 19.5MeV deuterons, the maximum deuteron energy obtainable with the MC-40 cyclotron. [Copyright &y& Elsevier]

Unconjugated bilirubin (UCB) is the end-product of heme catabolism in the intravascular compartment. Although beneficial for human health when mildly elevated in the body, when present at greater than a critical threshold concentration, UCB exerts toxic effects that are related to its physico-chemical properties, particularly affecting the central nervous system. The aim of the present study was to characterize bilirubin-10-sulfonate (ranarubin), a naturally occurring bile pigment, including determination of its mixed acidity constants (pK a * ). Thanks to the presence of the sulfonic acid moiety, this compound is more polar compared to UCB, which might theoretically solve the problem with an accurate determination of the UCB pK a * values of its propionic acid carboxylic groups. Bilirubin-10-sulfonate was synthesized by modification of a previously described procedure; and its properties were studied by mass spectrometry (MS), nuclear magnetic resonance (NMR), infrared (IR), and circular dichroism (CD) spectroscopy. Determination of pK a * values of bilirubin-10-sulfonate and UCB was performed by capillary electrophoresis with low pigment concentrations in polar buffers. The identity of the synthesized bilirubin-10-sulfonate was confirmed by MS, and the pigment was further characterized by NMR, IR, and CD spectroscopy. The pK a values of carboxylic acid moieties of bilirubin-10-sulfonate were determined to be 5.02, whereas those of UCB were determined to be 9.01. The physico-chemical properties of bilirubin-10-sulfonate were partially characterized with low pK a * values compared to those of UCB, indicating that bilirubin-10-sulfonate cannot be used as a surrogate pigment for UCB chemical studies. In addition, using a different methodological approach, the pK a * values of UCB were found to be in a mildly alkaline region, confirming the conclusions of a recent critical re-evaluation of this specific issue.

Bilirubin is degraded in the human gut by microflora into urobilinoids. In our study we investigated whether the bilirubin-reducing strain of Clostridium perfringens can reduce bilirubin ditaurate (BDT), a bile pigment of some lower vertebrates, without hydrolysis of the taurine moiety. C. perfringes was incubated under anaerobic conditions with BDT; reduction products were quantified by spectrophotometry and separated by TLC. Based on Rf values of BDT reduction products and synthetic urobilinogen ditaurate, three novel taurine-conjugated urobilinoids were identified. It is likely that bilirubin-reducing enzyme(s) serve for the effective disposal of electrons produced by fermentolytic processes in these anaerobic bacteria.