Detail of "23911-26-4"

Reference

New indium-111 labeled biotin derivatives for improved immunotargeting

New indium-111 labeled biotin derivatives for improved immunotargeting. Virzi, F.; Fritz, B.; Rusckowski, M.; Gionet, M.; Misra, H.; Hnatowich, D. J. (Med. Cent., Univ. 139384-83-1 and 23911-26-4 are cas registry numbers. These chemicals are also mentioned in this article. Massachusetts, Worcester, MA 01655, USA). Nucl. Med. Biol., 18(7), 719-26 (English) 1991. CODEN: NMBIEO. ISSN: 0883-2897. DOCUMENT TYPE: Journal CA Section: 8 (Radiation Biochemistry) Section cross-reference(s): 28, 63 Investigations into the use of streptavidin-conjugated antibodies and labeled biotin to improve radioimmunotargeting have shown background levels drastically reduced over the conventional approach. Nevertheless, accumulation of 111In-biotin in normal tissue as well as streptavidin-independent accumulation in tumor, was obsd. In this work, the effect of altering the biotin mol. to reduce this nonspecific uptake without decreasing specific localization has been investigated. Three EDTA and DTPA derivs. of biotin were synthesized and investigated along with a com. biotin deriv. (DTPA-B2). The labeled biotin chelates were administered i.p. to normal mice implanted with avidin beads in one thigh. A wide variation in biodistribution was seen among the biotin derivs. The most favorable results were obtained with biotinyl-hydrazino-EDTA (EDTA-B1), which showed the lowest accumulation in normal tissues but equiv. uptake in the target with respect to the other compds. Averaged over 8 tissues sampled, the target-to-nontarget ratio was 140 vs 9 for EDTA-B1 vs DTPA-B2 at 24 h post administration. Similar observations were made in culture with 2 tumor cell lines. Pos. accumulation of both DTPA-B2 and EDTA-B1 was measured in tumor cells independent of streptavidin-antibody conjugate, however in the case of the latter deriv., this accumulation was 3-5 fold lower. These studies show that modification of the biotin species can alter accumulation in normal tissues as well as the antibody-streptavidin independent accumulation in tumor tissue. .

Radiolabeled biomolecules with rhenium-186: potential for radioimmunotherapy

Radiolabeled biomolecules with rhenium-186: potential for radioimmunotherapy. Quadri, Syed M.; Wessels, Barry W. (Dep. Radiol., George Washington Univ., Washington, DC 20037, USA). Nucl. Med. Biol., 13(4), 447-51 (English) 1986. CODEN: NMBIEO. ISSN: 0883-2897. DOCUMENT TYPE: Journal CA Section: 8 (Radiation Biochemistry) 186Re has been theor. detd. to be among the best therapy radiolabels due to its unique half-life, particulate and g emissions, and chelation properties.Several reagents with their cas registry numbers 14998-63-1 and 23911-26-4 are used here. Traditionally, Re chelates have been synthesized by the Sn redn. method at low pH, which frequently produces denaturation of acid-labile proteins. A comparative study has been carried out to assess 3 techniques of reducing 186ReO4- to label biol. active macromols. [i.e., human serum albumin (HSA), anti-human serum albumin antibody (HSA-Ab), and a monoclonal antibody to T-cells (T-101)]. These expts. showed that stannous and dithionite redn. methods provide for an overall labeling yield of 5-18% with an assocd. immunoreactivity of 12-40%. The H3PO2 redn. method, however, yielded no usable radiolabeled product. The prepn. of 186Re-DTPA-HSA produced an 18.2% radiochem. yield (7.4 ′ 106 Bq/mg) and 40% retention of binding affinity. Using the stannous or dithionite redn. methods for the radiolabeling of HSA-Ab and T-101 resulted in a relatively low yield (9%), but the labeled product retained binding affinity of 12-25% with protein A. .