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K Wakisaka

Publications and source records attributed to K Wakisaka.

At least 19 recordsLinked to original sources
PubMed1999

Chemical design of radiolabeled antibody fragments for low renal radioactivity levels.

The renal uptake of radiolabeled antibody fragments presents a problem in targeted imaging and therapy. We hypothesized that the renal radioactivity levels of radiolabeled antibody fragments could be reduced if radiolabeled compounds of urinary excretion were released from glomerularly filtered antibody fragments before they were incorporated into renal cells by the action of brush border enzymes, present on the lumen of renal tubules. 3'-[131I]Iodohippuryl N(epsilon)-maleoyl-L-lysine ([131I]HML) was conjugated with a thiolated Fab fragment because the glycyl-lysine sequence in HML is a substrate for a brush border enzyme and metaiodohippuric acid is released by cleavage of the linkage. Fab fragments were also radiolabeled by direct radioiodination (125I-Fab) or by conjugation with meta-[125I]-iodohippuric acid via an amide bond [N-(5-maleimidopentyl) 3'-iodohippuric acid amide ([125I]MPH-Fab)] or an ester bond [maleimidoethy 3'-iodohippurate ([125I]MIH-Fab)] by procedures similar to those used for [131I]HML-Fab. In biodistribution experiments in mice, [131I]HML-Fab demonstrated markedly low renal radioactivity levels with kidney:blood ratios of radioactivity of 1 from 10 min to 1 h due to rapid release of meta-[131I]iodohippuric acid. [125]MIH-Fab and 1251-Fab reached their peak ratios of 3.8 and 7.3 at 1 h, respectively, and [125I]MPH-Fab showed the maximum ratio of 16.8 at 6 h. In subcellular distribution studies, both [125I]MIH-Fab and 125I-Fab showed migration of radioactivity from the membrane to the lysosomal fraction of the renal cells from 10 to 30 min postinjection, whereas the majority of the radioactivity was detected only in the membrane fraction after administration of [131I]HML-Fab at both time points. In nude mice, [131I]HML-Fab showed one-quarter of the renal radioactivity of simultaneously administered 125I-Fab without impairing the target radioactivity levels 3 h after injection. These findings indicated that HML is a useful reagent for targeted imaging and therapy using antibody fragments as vehicles. These findings also suggested that the radiochemical design of radiolabeled antibody fragments that liberate radiometabolites of urinary excretion from antibody fragments by the action of brush border enzymes may constitute a new strategy for reducing the renal radioactivity levels of antibody fragments.

Animals↗
PubMed1997

A novel radioiodination reagent for protein radiopharmaceuticals with L-lysine as a plasma-stable metabolizable linkage to liberate m-iodohippuric acid after lysosomal proteolysis.

Radiochemical design of polypeptides using metabolizable linkages would be attractive to enhance target-selective localization of radioactivity for diagnostic and therapeutic nuclear medicine. However, while use of ester bonds as the linkage allows selective release of the designed radiometabolite from covalently conjugated polypeptides after lysosomal proteolysis in nontarget tissues, low plasma stability of ester bonds causes a decrease in radioactivity levels of the target. In pursuit of new metabolizable linkages that provide stable attachment of radiolabels with polypeptide in plasma while facilitating rapid and selective release of designed radiometabolites of rapid urinary excretion in lysosomes, a new radioiodination reagent with L-lysine as the metabolizable linkage to liberate m-iodohippuric acid (L-HML) was designed and synthesized. Stabilities of the metabolizable linkage in serum and cleavabilities of the linkage in lysosomal proteolysis in hepatic cells were investigated after conjugation of [131I]-L-HML with galactosyl-neoglycoalbumin (NGA). For comparison, a radioiodination reagent with an ester bond to release m-iodohippuric acid (MIH) was conjugated with NGA under similar conditions. When incubated in human serum, [131I]-L-HML-NGA liberated less than 3% of the initial radioactivity after 24 h, whereas [125I]MIH-NGA released more than 60% of its radioactivity during the same interval. In biodistribution studies, [131I]-L-HML-NGA demonstrated radioactivity elimination from murine liver at a rate and excretion route similar to [125I]MIH-NGA. Analyses of murine urine after injection of [131I]-L-HML-NGA indicated a single radioactivity peak at fractions identical to those of m-iodohippuric acid. Biodistribution studies of radioiodinated NGAs with D-lysine or cadaverine as the linkages demonstrated a delayed elimination rate from murine liver with significantly higher radioactivity being excreted in the feces at 24 h postinjection. Thus, L-HML is the first reagent that allows stable attachment of radiolabel with polypeptide in serum while facilitating selective release of a radiometabolite with rapid urinary excretion from covalently conjugated polypeptides after lysosomal proteolysis at a rate similar to that of ester bonds. Thus, L-HML is potentially useful for the radioiodination of polypeptides for diagnostic and therapeutic purposes.

Albumins↗
PubMed1997

Allelic variants of the human MHC class I chain-related B gene (MICB).

The human major histocompatibility complex (MHC) is located within a 4 megabase segment on chromosome 6p21.3. Recently, a highly divergent MHC class I chain-related gene family, MIC was identified within the class I region. The MICA and MICB genes in this family have unique patterns of tissue expression. The MICA gene is highly polymorphic, with more than 20 alleles identified to date. To elucidate the extent of MICB allelic variations, we sequenced exons 2 (alpha 1), 3 (alpha 2), 4 (alpha 3), and 5 (transmembrane) as well as introns 2 and 4 of this gene in 46 HLA homozygous B-cell lines. We report the identification of eleven alleles based on seven non-synonymous, two synonymous, and four intronic nucleotide variations. Interestingly, one allele has a nonsense mutation resulting in a premature termination codon in the alpha 2 domain. Thus, MICB appears to have fewer alleles than MICA, not unlike the allelic ratio between the HLA-C and -B loci. A preliminary linkage analysis of the MICB alleles with those of the closely located MICA and HLA-B genes revealed no conspicuous linkage disequilibrium between them, implying the presence of a potential recombination hotspot between the MICB and MICA genes.

Alleles↗
PubMed1997

Monoclonal antibody #5-2-26 recognizes the phosphatase-sensitive epitope of rabies virus nucleoprotein.

We prepared monoclonal antibodies (MAbs) against the rabies virus N protein, among which one antibody (MAb 5-2-26) was shown to lack reactivity with the phosphatase-treated N protein. The MAb was able to recognize the sodium dodecyl sulfate (SDS)-denatured N protein. The MAb did not recognize the N-protein analogues produced in Escherichia coli (E. coli), indicating that the N-gene products were not normally processed in E. coli after translation. On the other hand, the MAb reacted normally with N-gene products produced in COS-7 cells, but not with those produced in the presence of K-252a (a protein kinase inhibitor of a broad spectrum). The MAb displayed weak cross-reactivity with the Triton-insoluble network structures composed of several components, while another phosphoprotein (M1) of the virus was not recognized at all. These results suggest that MAb 5-2-26 preferentially recognizes a phosphatase-sensitive linear epitope of N protein, which may enable further investigations to be conducted on the mechanism of N-protein phosphorylation and its role(s) in virus replication.

Animals↗
PubMed1997

Identification of a novel HLA-B allele (B*4202) in a Saudi Arabian family with Behçet's disease.

A new HLA-B antigen, tentatively called HLA-B42AND, was identified as a B42 serologic variant in a Saudi Arabian family. DNA sequencing analysis of the second and third exon of this new B allele revealed that B42AND was identical to B*4201 except for a single T to C substitution at position 97 of exon 2. This substitution results in histidine (CAC) at codon 9 in B42AND instead of tyrosine (TAC) in B*4201. The antigen frequency of B42AND in a Saudi Arabian population was around 10%. This novel B42AND has officially been named HLA-B*4202.

Alleles↗
PubMed1996

Reassessment of diethylenetriaminepentaacetic acid (DTPA) as a chelating agent for indium-111 labeling of polypeptides using a newly synthesized monoreactive DTPA derivative.

Previous studies on indium-111 (111In) labeling of polypeptides and peptides using cyclic diethylenetriaminepentaacetic dianhydride (cDTPA) as a bifunctional chelating agent (BCA) have indicated that DTPA might be a useful BCA for 111In labeling of polypeptides at high specific activities when DTPA can be incorporated without inducing intra- or intermolecular cross-linking. To investigate this hypothesis, a monoreactive DTPA derivative with a maleimide group as the peptide binding site (MDTPA) was designed and synthesized. A monoclonal antibody (OST7, IgG1) was used as a model polypeptide, and conjugation of MDTPA with OST7, 111In radiolabeling of MDTPA-OST7, and the stability of 111In-MDTPA-OST7 were investigated using cDTPA and benzyl-EDTA derivatives as references. SDS-PAGE analysis demonstrated that while cDTPA induced intramolecular cross-linking, no such undesirable side reactions were observed with MDTPA. MDTPA generated 111In-labeled OST7 with high radiochemical yields at higher specific activities than those produced using cDTPA and benzyl-EDTA derivatives as the BCAs. Incubation of each 111In-labeled OST7 in human serum indicated that MDTPA generated 111In-labeled OST7 of much higher and a little lower stability than those derived from cDTPA and benzyl-EDTA derivatives, respectively. These findings indicated that the low in vivo stability of cDTPA-conjugated antibody reported previously is not attributable to low stability of 111In-DTPA but to formation of intramolecular cross-linking during cDTPA conjugation reactions. The present study also indicated that MDTPA and its precursor, the tetra-tert-butyl derivative of DTPA, would be useful BCAs for 111In radiolabeling of polypeptides that have rapid blood clearance with high specific activities.

Chelating Agents↗
PubMed1996

Stability of a metabolizable ester bond in radioimmunoconjugates.

Ester bonds have been used as metabolizable linkages to reduce radioactivity levels in non-target tissues following the administration of antibodies labeled with metallic radionuclides. In this radiochemical design of antibodies, while the ester bonds should be cleaved rapidly in non-target tissues, high stability of the ester bonds in plasma is also required to preserve target radioactivity levels. To assess the structural requirements to stabilize the ester bond, a new benzyl-EDTA-derived bifunctional chelating agent with an ester bond, (1-[4-[4-(2- maleimidoethoxy)succinamido]benzyl]ethylenediamine-N,N,N',N' -tetraacetic acid; MESS-Bz-EDTA), was developed. MESS-Bz-EDTA was coupled with a thiolated monoclonal antibody (OST7, IgG1) prepared by reducing its disulfide bonds to introduce the ester bond close and proximal to the antibody molecule. For comparison, 1-[4-(5- maleimidopentyl)aminobenzyl]ethylenediamine-N,N,N',N'-tetraacetic acid (EMCS-Bz-EDTA) and meleimidoethyl 3-[131I]iodohippurate (MIH) was coupled to OST7 under the same conjunction chemistry. When incubated in 50% murine plasma or a buffered-solution of neutral pH, OST7-MESS-Bz-EDTA-111In rapidly released the radioactivity, and more than 95% of the initial radioactivity was liberated after a 24 h incubation in both solutions, due to a cleavage of the ester bond. On the other hand, only about 20% of the radioactivity was released from OST7-MIH-131I in both solutions during the same incubation period. In mice biodistribution studies, while a slightly faster radioactivity clearance from the blood with less radioactivity levels in the liver and kidneys was observed with OST7-MIH-131I than with OST7-EMCS-Bz-EDTA-111In, OST7-MESS-Bz-EDTA-111In indicated radioactivity clearance from the blood much faster than and almost comparable to that of OST7-MIH-131I and succinamidobenzyl-EDTA-111In, respectively. These findings as well as previous findings on radiolabeled antibodies with ester bonds suggested that while an introduction of an ester bond close to an antibody molecule stabilized the ester bond against esterase access, chemical structures of the linkages and radiolabels attached to the ester bonds play a significant role in the chemical stability of the ester bond. This may explain the different stability of the ester bonds in radioimmunoconjugates so far reported.

Animals↗
PubMed1995

Radiolabeled metabolites of proteins play a critical role in radioactivity elimination from the liver.

We have recently reported that the behavior of radiolabeled metabolites in the liver appears to be responsible for the hepatic radioactivity levels after administration of protein radiopharmaceuticals. To better understand the role played by radiolabeled metabolites in hepatic radioactivity levels, two benzyl-EDTA derivatives rendering different radiolabeled metabolites, 1-(4-isothiocyanatobenzyl)ethylenediaminetetraacetic acid (SCN-Bz-EDTA) and 1-[p-(5-maleimidopentyl)aminobenzyl]ethylenediaminetetraacetic acid (ECMS-Bz-EDTA), were selected as bifunctional chelating agents (BCAs), and 111In labeling of galactosyl-neoglycoalbumin (NGA) and mannosyl-neoglycoalbumin (NMA) was performed. Biodistribution of radioactivity in mice and subcellular distribution of radioactivity in hepatocytes were then compared. After accumulation in hepatic parenchymal cells, NGA-EMCS-Bz-EDTA-111In rendered a faster elimination rate of radioactivity from the liver than NGA-SCN-Bz-EDTA-111In. Although each 111In-NMA exhibited a delayed elimination rate of radioactivity from the liver compared to the 111In-NGA counterpart, NMA-EMCS-Bz-EDTA-111In showed faster elimination rate of radioactivity than NMA-SCN-Bz-EDTA-111In. Analyses of radioactivity excreted in feces and urine and remaining in the liver indicated that both BCAs rendered mono-amino acid adducts as the major radiolabeled metabolites (cysteine-EMCS-Bz-EDTA-111In and lysine-SCN-Bz-EDTA-111In), which were generated in both cell types of the liver within 1 h postinjection. Subcellular distribution of radioactivity indicated that the radioactivity was copurified with lysosomes. These results demonstrate that although in vivo stability of radiometal chelates is essential, the biological properties of the radiolabeled metabolites generated after lysosomal proteolysis in hepatocytes play a critical role in radioactivity elimination from the liver.

Animals↗
PubMed1994

Maleimidoethyl 3-(tri-n-butylstannyl)hippurate: a useful radioiodination reagent for protein radiopharmaceuticals to enhance target selective radioactivity localization.

In pursuit of radiolabeled monoclonal antibodies (mAbs) with rapid urinary excretion of radioactivity from nontarget tissues, radioiodinated mAbs releasing a m-iodohippuric acid from the mAbs in nontarget tissues were designed. A novel reagent, maleimidoethyl 3-(tri-n-butylstannyl)hippurate (MIH), was synthesized by reacting N-(hydroxyethyl)maleimide with N-Boc-glycine before coupling with N-succinimidyl 3-(tri-n-butylstannyl)benzoate (ATE). MIH possessed a maleimide group for mAb conjugation and a butylstannyl moiety for high-yield and site-specific radioiodination, and the two functional groups were linked via an ester bond to release m-iodohippuric acid. To investigate the fate of radiolabels after lysosomal proteolysis, hepatic parenchymal cells were used as a model nontarget tissue and 131I-labeled MIH was conjugated with galactosyl-neoglycoalbumin (NGA). Further conjugation of [131I]MIH with a mAb against osteogenic sarcoma (OST7) after reduction of its disulfide bonds was followed up. In murine biodistribution studies, [131I]MIH-NGA exhibited rapid accumulation in the liver followed by radioactivity elimination from the liver at a rate that was identical to and faster than those of 131I-labeled NGA via direct iodination ([131I]NGA) and [131I]ATE-labeled NGA, respectively. While [131I]NGA indicated high radioactivity levels in the murine neck, stomach, and blood, such increases in the radioactivity count were not detectable by the administration of either [131I]MIH-NGA or [131I]ATE-NGA. At 6 h postinjection of [131I]MIH-NGA, 80% of the injected radioactivity was recovered in the urine. Analyses of urine samples indicated that m-iodohippuric acid was the sole radiolabeled metabolite. In biodistribution studies using [131I]-MIH-OST7 and [131I]ATE-OST7, while both 131I-labeled OST7s registered almost identical radioactivity levels in the blood up to 6 h postinjection, the former demonstrated a lower radioactivity level than [131I]ATE-OST7 in nontarget tissues throughout the experiment. Such chemical and biological characteristics of MIH would enable high target/nontarget ratios in diagnostic and therapeutic nuclear medicine using mAbs and other polypeptides.

Albumins↗
PubMed1994

Self-reported prevalence of non-insulin-dependent diabetes mellitus in the 1st (Issei) and 2nd (Nisei) generation of Japanese-Brazilians over 40 years of age.

The immigration of Japanese people to Brazil began in 1908 with two major waves, from 1925 to 1940 and from 1952 to the 1960s. Brazil has the largest population (about 1,288,000) of Japanese origin outside Japan with varying age groups. A mortality study revealed that diabetes as an underlying cause of death was higher in the first-generation Japanese than in Japan (3.4 vs. 1.9 per 100,000 for men, and 7.2 vs. 1.9 for women). The self-reported prevalences of known diabetes in subjects aged 40 years or older were obtained by questionnaires from three sources. In six Japanese cultural associations in Säo Paulo city, the prevalences were 9.7% and 6.9% for the first generation (mean age 61.5 years) and for the second generation (mean age 40.0 years), respectively. Age-adjusted prevalences, according to the Brazilian population in the 1980 national census, were 6.9% and 8.1% for the first and second generations. According to a study carried out as a part of a socioeconomic census of the Japanese population in Brazil, the prevalences of diabetes were 7.4% and 5.2%, and the age-adjusted prevalences were 5.3% and 5.8% in the first and second generations, respectively. Another study carried out for employees of a bank, owned by Japanese-Brazilian community members, revealed crude prevalences of diabetes in the first and second generations of 7.1% and 4.2%, and age-adjusted prevalences of 7.3% and 8.2%, respectively. These data indicate an increased prevalence of diabetes in this population compared to Japan, suggesting the importance of environmental factors in the pathogenesis of diabetes.

Adult↗
PubMed1994

A biological method to evaluate bifunctional chelating agents to label antibodies with metallic radionuclides.

UNLABELLED: Since the lysosome is a common organelle for protein digestion, pursuing the fate of radiolabeled metabolites after lysosomal proteolysis in liver cells is ideal to evaluate bifunctional chelating agents (BCAs). METHODS: We used galactosyl-neoglycoalbumin (NGA) and mannosyl-neoglycoalbumin (NMA) as carrier proteins for hepatic parenchymal and nonparenchymal cells, respectively. These proteins were labeled with 111In using 1-(4-isothiocyanatobenzyl)ethylenediaminetetraacetic acid (SCN-Bz-EDTA) as a model. RESULTS: NGA-SCN-Bz-EDTA-111In exhibited rapid accumulation in the hepatic parenchymal cells, followed by hepatobiliary excretion of the metabolites with an elimination rate that was faster and much slower than that of NGA-DTPA-111In and NGA-131I, respectively. This metabolite represented all the radioactivity registered in the liver at 1 hr postinjection. Subcellular distribution studies indicated the metabolites were located only in the lysosome fraction, and the difference in elimination rates of the metabolites from the lysosome fraction was responsible for the variations in radioactivity clearance from the cells. CONCLUSION: The biological characteristics of radiolabeled metabolites play a critical role in eliminating the radiolabel from liver cells. The present method portrays a highly useful model to pursue the fate of radiolabeled metabolites in the liver.

Albumins↗
PubMed1994

Discriminated release of a hippurate-like radiometal chelate in nontarget tissues for target-selective radioactivity localization using pH-dependent dissociation of reduced antibody.

UNLABELLED: To achieve high and selective target radioactivity localization by monoclonal antibodies (Mabs) labeled with metallic radionuclides, the discriminated release of a hippurate-like radiometal chelate in nontarget tissues was performed using chemically modified Mabs. METHODS: The disulfide bonds of a Mab against osteogenic sarcoma (OST7, IgG1) were reduced and 67Ga chelate of succinyldeferoxamine (SDF) was conjugated proximal to the Mab molecule via an ester bond with exposed thiol groups (67Ga-DFO-MESS-redOST7), which would impair esterase access to the ester bond of 67Ga-DFO-MESS-redOST7 due to the steric interference induced by bulky antibody molecule, stabilizing the ester bond in plasma and on the target cell's surface. Gallium-67-SDF was also conjugated to OST7 via an ester bond with 2-iminothiolane to render the ester bond in a position distal from the OST7 molecule (67Ga-DFO-MESS-IT-OST7). RESULTS: Although SDS-PAGE analyses of 67Ga-DFO-MESS-redOST7 showed a partial cleavage of its disulfide bonds, size-exclusion HPLC and cell binding assays indicated that the IgG structure and immunoreactivity of this conjugate were preserved in a neutral buffer and plasma of the systemic circulation. CONCLUSION: The present radiochemical design of an antibody utilizing pH-dependent dissociation would constitute a promising approach in establishing selective target radioactivity localization by Mabs.

Animals↗
PubMed1984

Mutagenic 1-nitropyrene in wastewater from oil-water separating tanks of gasoline stations and in used crankcase oil.

Wastewater collected from oil-water separating tanks of ten gasoline stations for a year was fractionated into diethyl ether-soluble neutral, acidic, and basic fractions. Mutagenicity of these fractions was measured with Salmonella typhimurium strains TA98 and TA100 in the presence or absence of S9 mix. The neutral fractions showed high mutagenicity in the absence of S9 mix. Each neutral fraction was subjected to high-performance liquid chromatography (HPLC) and fractionated. A 1-nitropyrene(1-NP)-corresponding fraction was collected and analyzed by gas chromatography-mass spectrometry (GC-MS) and HPLC to prove that wastewater contains 1-NP and to quantitate 1-NP in wastewater. GC-MS patterns showed the following molecular and fragment ion peaks of 1-NP: 247, 217, 201, and 189. The amount of 1-NP in 36 samples of wastewater was 4.2-25,600 ng per liter of wastewater, and 1-NP accounted for 0.3-58.5% of the total mutagenicity of the neutral fractions. The other 19 samples of wastewater did not contain any detectable 1-NP. The mutagenicity of wastewater may be due to water from car washing and contamination by used crankcase oil. A Soxhlet extract of crankcase oil used in a gasoline was fractionated into three fractions as above. Mutagenicity was measured with strains TA98, TA100, TA98NR, and TA98/1,8-DNP6 in the absence or presence of S9 mix. The neutral fraction showed the highest mutagenicity with strain TA98 in the absence of S9 mix, and its mutagenicity was decreased in strains TA98NR and TA98/1,8-DNP6. The latter result indicates that the used engine-oil contained 1-NP and dinitropyrenes. Actually, the amounts of 1-NP and 1,6-diNP in used crankcase oil were 138 and 2.0 ng per ml of oil, respectively, and these concentrations accounted for 0.45 and 2.7%, respectively, of the total mutagenicity of the neutral fraction with strain TA98 in the absence of S9 mix. Moreover, the concentrations of 1-NP and 1,6-diNP in used crankcase oil of a diesel engine were 349 and 31 ng per ml of oil, respectively, accounting for 0.9 and 12%, respectively, of the total mutagenicity of the neutral fraction in the same assay system.

Chromatography, High Pressure Liquid↗
PubMed1982

Biotransformation of 1-nitropyrene in intestinal anaerobic bacteria.

Mutagenic nitroaromatic compounds have recently been found in photocopies, urban atmosphere, automobile exhaust and wastewater. 1-Nitropyrene (1-NP) is readily formed when pyrene, ubiquitous in the environment, is exposed to nitrogen dioxide in the urban atmosphere or in automobile exhaust, and is highly mutagenic, inducing 449 his+ revertants/plate/nmol from Salmonella typhimurium strain TA98 in the absence of S9 fraction in the Salmonella-microsome test. It is possible to swallow sputum or some food containing 1-NP and it would come into contact with the normal bacterial flora. We determined the 1-NP nitroreductase activity in environmental and laboratory bacterial strains. We found that the mutagenicity of 1-NP mixed with the feces of a healthy man or a culture of anaerobic bacteria was decreased. The product proved to be 1-aminopyrene (1-AP), based on its fluorescence spectrum, its mass spectrum, and its characteristic thin layer chromatographic and high performance liquid chromatographic patterns. The 1-NP nitroreductase activity of aerobic bacteria was low, but crude extracts from the anaerobic bacteria, i.e., Bacteroides fragilis, B. thetaiotaomicron, B. vulgatus, Fusobacterium mortiferum, F. nucleatum, Clostridium perfringens, C. sporogenes, Bifidobacterium adolescentis, B. bifidum, Eubacterium lentum, E. limosum, and Peptostreptococcus anaerobius, all easily converted 1-NP to 1-AP and proportionally decreased the mutagenic activity of 1-NP.

Adult↗
PubMed1980

Studies on the synthesis of chemotherapeutics. 10. Synthesis and antitumor activity of N-acyl- and N-(alkoxycarbonyl)-5-fluorouracil derivatives.

A number of N-acyl and N-(alkoxycarbonyl)-5-fluorouracil derivatives possessing, for example, benzoyl, o-toluyl, acetyl, propionyl, heptanoyl, ethoxycarbonyl, phenoxycarbonyl, and benzyloxycarbonyl groups as N1 and/or N3 substituents were synthesized, and their antitumor activities were evaluated. The synthesis was achieved by a direct and two-step acylation of 5-fluorouracil and by selective N1-deacetylation of N1-acetyl-N3-substituted-5-fluorouracil under appropriate reaction conditions. Several N3-benzoyl- and N3-o-toluyl-5-fluorouracil derivates and showed significant activity against experimental tumor, and N1-acetyl-N3-o-toluyl-5-fluorouracil was found to be most promising among them. Further investigation revealed 12 to retain higher activity toward various tumors, with lower toxicity and good blood level, than either 1 or FT-207, even for oral administration.

Animals↗