Haemolytic disease of fetus and newborn caused by ABO antibodies in a cisAB offspring

ABO hemolytic disease of fetus and newborn (ABO-HDFN) occurs almost exclusively in infants of blood group A or B who are born to group O mothers because IgG anti-A or -B occurs more commonly in group O than in group A or B individuals. We report a case of clinically significant ABO-HDFN where the mother was blood group O with elevated IgG anti-A and anti-B titers and delivered a child with an A2B phenotype. This unusual ABO constellation between mother and infant was based on the inheritance of a rare ABO allele encoding for a glycosyltransferase capable of synthesizing both A and B antigens. Because both anti-A and anti-B antibodies may have been involved in hemolysis in this case, it may be relevant to consider the cisAB phenomenon when monitoring ABO-incompatible pregnancies and births.

Seizures accelerate forgetting in patients with left-sided temporal lobe epilepsy

Ten patients with refractory temporal lobe epilepsy performed a word-position association learning task every 24 hours during video EEG monitoring. On 55 occasions recall performance was tested 30 minutes and 24 hours after the initial learning phase. Patients with left- but not right-sided temporal lobe epilepsy exhibited impaired retention of word position if a seizure had occurred during the preceding 24-hour interval. Seizures may impair the consolidation of memory in patients with left-sided temporal lobe epilepsy beyond the chronic memory deficits caused by the underlying pathology.

DNA alkylation by leinamycin can be triggered by cyanide and phosphines

Previous work has shown that alkylation of DNA by the antitumor agent leinamycin (1) is potentiated by reaction of the antibiotic with thiols. Here, it is shown that other soft nucleophiles such as cyanide and phosphines can also trigger DNA alkylation by leinamycin. Overall, the results suggest that reactions of cyanide and phosphines with leinamycin produce the oxathiolanone intermediate (2), which is known to undergo rearrangement to the DNA-alkylating episulfonium ion 4.

DNA binding and alkylation by the "left half" of azinomycin B

Azinomycin B (also known as carzinophilin A) contains two electrophilic functional groups-an epoxide and an aziridine residue-that react with nucleophilic sites in duplex DNA to form cross-links at 5'-dGNT and 5'-dGNC sequences. Although the aziridine residue of azinomycin is undoubtedly required for cross-link formation, analogues containing an intact epoxide group but no aziridine residue retain significant biological activity. Azinomycin epoxide analogues (e.g., 5 and 6) are of interest due to their potent biological activity and because there is evidence that azinomycin may decompose in vivo to yield such compounds. To investigate the chemical events underlying the toxicity of azinomycin epoxides, DNA binding and alkylation by synthetic analogues of azinomycin B (6, 8, and 9) that comprise the naphthalene-containing "left half" of the antibiotic have been investigated. The epoxide-containing analogue of azinomycin (6) efficiently alkylates guanosine residues in duplex DNA. DNA alkylation by 6 is facilitated by noncovalent binding of the compound to the double helix. The results of UV-vis absorbance, fluorescence spectroscopy, DNA winding, viscometry, and equilibrium dialysis experiments indicate that the naphthalene group of azinomycin binds to DNA via intercalation. Equilibrium dialysis experiments provide an estimated binding constant of (1.3 +/- 0.3) x 10(3) M(-)(1) for the association of a nonalkylating azinomycin analogue (9) with duplex DNA. The DNA-binding and alkylating properties of the azinomycin epoxide 6 provide a basis for understanding the cytotoxicity of azinomycin analogues which contain an epoxide residue but no aziridine group and may provide insight into the mechanisms by which azinomycin forms interstrand DNA cross-links.