Convenient and Efficient Syntheses of Oligodeoxyribonucleotides Containing O 6-(Carboxymethyl)Guanine and O 6-(4-Oxo-4-(3-Pyridyl)Butyl)Guanine

O ⁶-(carboxymethyl)guanine (O ⁶-CMG) and O ⁶-(4-oxo-4-(3-pyridyl)butyl)guanine (O ⁶-pobG) are toxic lesions formed in DNA following exposure to alkylating agents. O ⁶-CMG results from exposure to nitrosated glycine or nitrosated bile acid conjugates and may be associated with diets rich in red meat. O ⁶-pobG lesions are derived from alkylating agents found in tobacco smoke. Efficient syntheses of oligodeoxyribonucleotides (ODNs) containing O ⁶-CMG and O ⁶-pobG are described that involve nucleophilic displacement by the appropriate alcohol on a common synthetic ODN containing the reactive base 2-amino-6-methylsulfonylpurine. ODNs containing O ⁶-pobG and O ⁶-CMG were found to be good substrates for the S. pombe alkyltransferase-like protein Atl1.

[Supplemental materials are available for this article. Go to the publisher's online edition of Nucleosides, Nucleotides & Nucleic Acids to view the free supplemental file.]     

Niagara Blue 4B As A Fast Simple Stain for the Adenohypophysis

For differentiation of cells of the adenohypophysis, the Niagara blue 4B method requires no special preliminary fixative nor very fresh tissue, and requires no more time than routine hematoxylin-eosin (H-E) staining. The method requires fixation in 10% formalin. After processing to paraffin wax, deparaffinise and hydrate the sections and stain in 1% aqueous Niagara blue 4B solution for 2 min. Stain afterwards with hematoxylin for 1 min then differentiate, wash, dehydrate, clear and mount. This method can be used also for staining old HE slides by removing the covers, applying the Niagara blue 4B and restaining with eosin. The Niagara blue 4B combined with H-E gives the best and most colorful result. This method allows special staining of the adenohypophysis from human post-mortem material to become routine.     

Transience of Immune Responses to Tumour Antigens in Man

By examining serial serum samples from patients undergoing surgical removal of malignant tumours an increased incidence of tumour-specific antibodies has been detected. Antibody responses to tumour neoantigens seem to be transient, and this is held to account for the rarity of detections where a single sample of serum is examined.     

INCORPORATION OF TRITIATED THYMIDINE INTO THE SKIN AND HAIR FOLLICLES

Diurnal fluctuations in incorporation of tritiated uridine and tritiated thymidine are reported for full thickness skin and its two proliferative populations, the epidermal basal layer and the hair follicle germ or matrix. Recently developed techniques whereby these two populations can be studied independently were utilized. Resting (unplucked) skin and skin in the middle of the hair growth cycle (10 days after plucking) was studied. the diurnal fluctuations differed at these two stages of the hair cycle. Generally a single minimum level of activity was observed shortly after the beginning of the dark period of the day, i.e. after 18.00 hours.