Hematological changes produced in mice by ochratoxin A

The effects of ochratoxin A (5 mg/kg, intraperitoneal) on clotting time, hemoglobin, total count of red blood cells and white blood cells and differential count of white blood cells were studied in mice. This mycotoxin caused a significant decrease in the hemoglobin level and in the total count of red blood cells. Among white blood cells there was a significant increase in small lymphocytes and a significant fall in the count of neutrophils, basophils and monocytes in treated mice. The administration of ochratoxin A also prolonged the clotting time by more than 6-fold.

Alanine derivatives with reactive groups

The synthesis of diazoketone analogs of amino acids and associated problems were investigated with N-phthaloyl-DL-alanine serving as a model. The carboxyl was activated by conversion to the acid chloride or, under mild conditions, to the mixed anhydride obtained with ethyl chloroformate or dicyclohexylcarbodiimide; the product was reacted with diazomethane. Deblocking the phthaloyl group with hydrazine gave 3-amino-1-diazo-2-butanone as a well-characterized solid salt and as a less stable oil. Further reactions of the blocked diazoketone of DL-alanine, such as conversion to alpha-haloketones, Wolff rearrangement, and deuterium exchange on C-1 were investigated. 3-A-mino-1-diazo-2-butanone had moderate inhibitory activity against mouse mammary adenocarcinoma in cell culture.

Biochemical characteristics, metabolism, and antitumor activity of several acetylated hexosamines

We have synthesized several potential inhibitors and/or modifiers of the carbohydrate portion of plasma membrane glycoconjugates. These include fluorinated and actylated analogs of D-glucosamine, D-galactosamine, and D-mannosamine. These compounds have been tested to determine their effects on both[14C] glucosamine and [3H] leucine incorporation into glycoconjugate and on cell growth and viability using P-288 murine lymphoma cells maintained in tissue culture. The most cytotoxic agent tested was 2-acetamido-2-deoxy-1,3,4,6-tetra-O-acetyl-beta-D-glucopyranose or simply beta-pentaacetylglucosamine which prevented cell growth at 10(-4)-10(-3) M. beta-Pentaacetylglucosamine cytotoxicity was correlated with its high lipid solubility, having an octanol/water partition coefficient of 0.424 as compared with 0.278 for the alpha-anomer and 0.017 for N-acetylglucosamine. In vitro metabolism studies with [4C]- and/or [3H]-labeled pentaacetylglucosamine have indicated intracellular de-O-acetylation leading to the biosynthesis of UDP-N-acetylglucosamine, followed by the incorporation of this sugar into cellular glycoprotein. Concomitant with the formation of increased amounts of this nucleotide sugar, intracellular UTP and CTP pools fell to one third normal within 3 h after the administration of 1 mM pentaacetylglucosamine. At present it is unclear whether the cytotoxicity of beta-pentaacetylglucosamine or other similar agents is due to alterations in nucleotide and nucleotide-sugar pools causing a decrease in energy charge and polynucleotide biosynthesis or is due to a direct effect on membrane glycoconjugate biosynthesis.

Cysteine derivatives with reactive groups as potential antitumor agents

Cysteine derivatives having diazo ketone and chloro ketone functions have been prepared. In order to effect adequate protection for modifying the carboxyl group, cysteine was converted to a thiazolidine derivative I, which was then converted to the N-acetyl derivative VII. The active ester method or activation with DCC yielded the diazo ketone derivative VIII. Similar treatment of the parent compound I with DCC led to a self-condensation reaction giving a diketopiperazine VI. The diazo ketone derivative VIII has been used in preparing alpha-chloro ketone derivative X and a homologue of cysteine. Deblocking N-acetylated thiazolidine derivatives with various reagents did not proceed satisfactorily. Interaction of the N-acetylated blocked ester XII with trifluoroacetic acid opened the thiazolidine ring to give the N-acetylated blocked diester XIII and other products. The chloro ketone derivative X was found to have a moderate inhibitory activity against mouse mammary adenocarcinoma in cell culture. S-(1-Adamantyl)-L-cysteine was prepared and was found to be inactive.

Inhibitors of nucleoside transport. A structure-activity study using human erythrocytes

The passage of nucleosides across the plasma membrane of erythrocytes is a membrane-mediated process which is strongly inhibited by derivatives of 9-beta-D-ribofuranosylpurine (1) with S, O, or N atoms at the purine 6 position bearing variously substituted arylalkyl groups. In this structure-activity study, nucleoside derivatives were compared in respect to their ability to inhibit a transport-dependent aspect of nucleoside metabolism in erythrocytes, the synthesis of inosine from external guanosine and hypoxanthine. 6-Benzylthio, 6-benzylamino, and 6-benzyloxy derivatives of 1 were inhibitory at 10(-5)-10(-6) M and the similarity of their activities suggested that alkylation of the transporter as the mechanism of transport inhibition was unlikely. The hydrophobicity of the 6-position substituents appeared to contribute importantly to inhibitory activity. Although replacement of the ribofuranose moiety by other sugars reduced inhibitory activity, compounds with 9-butyl groups were inhibitory. 6-[(2-Hydroxy-5-nitrobenzyl)thio] derivatives of 1 were the most potent of the inhibitors tested, being active at about 10(-7) M.

Binding of the nucleoside transport inhibitor 4-nitrobenzylthioinosine to erythrocyte membranes

4-Nitrobenzylthioinosine (NBMPR), a potent nucleoside transport inhibitor, was prepared in two radioactive forms and the binding of these to erythrocyte ghosts was studied. Similar binding data were obtained with inhibitor containing 14C in the purine 8-position or in the benzyl 7-position, suggesting that the entire inhibitor molecule was bound. A saturable high-affinity mode of NBMPR binding was apparent; NBMPR bound in this way was not removed by washing, but was displaced by a related inhibitor of nucleoside transport, 2-hydroxy-5-nitrobenzylthioguanosine (HNBTGR). It is postulated that the high-affinity binding sites are the nucleoside transport elements of the erythrocyte membrane. From ghosts treated with 14C-NBMPR under conditions which assured binding of the high affinity type, 14C was recovered by extractions in the form of NBMPR. Thus, this mode of NBMPR binding is reversible and covalent linkages do not appear to be involved. A low affinity mode of NBMPR binding was also demonstrated; this appeared to be a partition of NBMPR between the medium and the membrane substance. This component of bound NBMPR was not displaced by HNBTGR and was removed by washing.

Detection of chlamydial antibodies in animal sera by double diffusion in gel

Postinoculation sera collected from pigeons, turkeys, guinea pigs, sheep, a calf, a rabbit, and a horse experimentally infected with various strains of Chlamydia psittaci yielded a high incidence of positive reactions when tested by double diffusion in gel. Antigen was a deoxycholate extract of SA-2 strain of C. trachomatis. Good correlation was obtained with results of complement fixation tests, whereas double diffusion in gel was less sensitive. Immunoelectrophoresis of the antigen revealed presence of two antigens in the extract.

Relationship of 13C to Vicinal 1H Coupling to the Torsion Angle in Uridine and Related Structures

Uracil was prepared enriched at C2 with carbon-13 and converted into uridine from which 2,5′-anhydro-1-β-D-ribo-furanosyl and 2,2′-anhydro-1-β-D-arabino-furanosyl uracil were prepared. The 13C2 to vicinal proton coupling constants for these compounds were measured and are compared in terms of the expected torsion angles defined by the two atoms. The evidence suggests the existence of a Karplus-type relationship as is found for vicinal proton coupling. The data establish the anti conformation for uridine in solution.

Mixed ligand complexes of cadmium(II)

Trichloro or tetrachloro cadmium(II) compounds were reacted with thiourea in ethanolic medium and mixed ligand anionic complexes having the formula M+(CdCl3•tu)−, where M is tetraethyl ammonium, tetraphenyl arsonium, and tetraphenyl phosphonium, have been characterized. The infrared spectra indicate the presence of both the quaternary halide and thiourea.