New developments in silvichemicals

A discussion of the activities of Crown Zellerbach Corporation in the field of developing, producing and worldwide marketing of pure chemicals of commerce from the forest, including comments on some new chemicals being developed.     

New developments in cytogenetics

Novel methods allowing to analyze the human genome make it possible to assess old questions such as the molecular basis of structural chromosome anomalies and the diathesis to aneuploidy. The architecture of the human genome as unravelled by the human genome sequencing project allows to explain the recurrence of microdeletions and microduplications caused by a non allelic homologous recombination involving segmental duplications created during the evolution of primates. This structural feature of the human genome is associated with a novel class of genetic diseases called genomic disorders as opposed to genetic diseases due to gene mutations. The study of the parental and cellular origin of aneuploidy shed new light on the different mechanisms controlling meiosis in man and woman. In addition it contributes to define the role of maternal age and genetic recombination on the behavior of chromosomes during meiosis. These new data greatly contribute to our understanding of human chromosomal diseases.     

Double contrast retrograde urethrography using viscous and gaseous contrast media in men

The authors present the literature and their own data on the use of a double contrast study of the urethra in 38 male patients with dysuria of various etiology. The investigations were performed with roentgeno-television control using viscid contrast substances (propyliodone) and gel-like triiodinated liquid contrast media (verografin, urografin, triombrast, etc.). A high informative value of the method in the detection of pathological changes in the urethra and the neck of the urinary bladder, lesser risk of the development and lesser severity of urethro-venous refluxes were noted.     

New developments in ancient genomics

Ancient DNA research is on the crest of a 'third wave' of progress due to the introduction of a new generation of DNA sequencing technologies. Here we review the advantages and disadvantages of the four new DNA sequencers that are becoming available to researchers. These machines now allow the recovery of orders of magnitude more DNA sequence data, albeit as short sequence reads. Hence, the potential reassembly of complete ancient genomes seems imminent, and when used to screen libraries of ancient sequences, these methods are cost effective. This new wealth of data is also likely to herald investigations into the functional properties of extinct genes and gene complexes and will improve our understanding of the biological basis of extinct phenotypes.