Characterization of the complete human elastin gene. Delineation of unusual features in the 5'-flanking region

Genomic clones encompassing the entire human elastin gene, including 11 kilobases flanking the ATG translation initiation codon, have been obtained and characterized by restriction enzyme analysis and extensive DNA sequencing. These analyses demonstrated that functionally distinct hydrophobic and cross-linking domains of the protein are segregated into separate exons throughout the gene. All exons are multiples of three nucleotides, and exon:intron borders always split codons in the same way which permits cassette-like alternative splicing. The 5'-flanking region lacks a canonical TATA sequence, is G + C-rich, and contains several SP1 binding sites and an AP2 binding site. Primer extension and S1 nuclease protection experiments indicate that transcription is initiated at multiple sites in the gene.

Structure of the bovine elastin gene and S1 nuclease analysis of alternative splicing of elastin mRNA in the bovine nuchal ligament

Genomic clones encompassing all the translated sequences, the 3' untranslated sequence, and 1 kb flanking the ATG translation initiation codon of bovine tropoelastin have been obtained and characterized by restriction enzyme analysis and extensive DNA sequencing. These analyses demonstrated that functionally distinct hydrophobic and cross-linking domains of the protein are segregated into separate exons throughout the gene. The putative promoter region lacks a TATA box, has an extremely high G+C content, and contains several SP1 binding sites. Comprehensive S1 analyses using probes covering the entire mRNA and RNA isolated from the nuchal ligament of bovine fetuses of different ages, neonate calves, and adult cows demonstrated that while only a single exon is alternatively spliced at high frequency, many exons are alternatively spliced at limited, variable frequencies. The results also suggest that such limited splicing is increased in the adult tissue relative to fetal and neonate tissues.

Conversion of IQ, a dietary pyrolysis carcinogen to a direct-acting mutagen by normal intestinal bacteria of humans

The dietary carcinogen, 2-amino-3-methyl-3H-imidazo[4,5-f]quinoline (IQ) is mutagenic in the Salmonella/microsomal mutagenicity assay when activated by microsomal enzymes. IQ is found in many cooked foods, notably fried beef and pork. In laboratory rodents IQ is carcinogenic. We showed that mixed and pure cultures of human intestinal anaerobes, notably Eubacterium spp., metabolized IQ to 2-amino-3,6-dihydro-3-methyl-7H-imidazo[4,5-f]quinoline-7-one (HOIQ). Unlike IQ, both the synthetic and bacterially produced HOIQ were direct-acting mutagens, i.e. active without microsomal activation. This new direct-acting mutagen, from the bacterial metabolism of a dietary pyrolysis carcinogen, raises new concerns about the possible role of this class of genotoxins in the etiology of human cancer.

The reciprocal partners of both the t(14; 18) and the t(11; 14) translocations involved in B-cell neoplasms are rearranged by the same mechanism

Both the t(14; 18) and the t(11; 14) chromosomal translocations are associated with human B-cell neoplasms. Sequence analysis of the regions on chromosomes 18q- and 11q- involved in the joining of chromosomes 14 and 18 and of chromosomes 11 and 14 during their respective translocations indicates the involvement of the DH region. There is a deletion of the region between the involved D segment and the JH region, and extranucleotides are present at the joining sites on the 18q- and on the 11q- chromosomes. We have previously reported that the joining region on chromosome 14q+ involved in both the t(11; 14) and the t(14; 18) translocations are structurally identical. We now report that the joining regions on chromosomes 11q- and 18q- involved in these two different translocations are also identical. Thus, these translocations arose by the same mechanisms. The deletions of the region between the involved segment and the JH region must likely occur during either a D-J recombination event on the 18q- and 11q- chromosomes following the translocations or, alternatively, during the D-J recombination event that results in the translocation.

DNA rearrangements in human follicular lymphoma can involve the 5' or the 3' region of the bcl-2 gene

In most human follicular lymphomas, the chromosome translocation t(14;18) occurs within two breakpoint clustering regions on chromosome 18, the major one at the 3' untranslated region of the bcl-2 gene and the minor one at 3' of the gene. Analysis of a panel of follicular lymphoma DNAs using probes for the first exon of the bcl-2 gene indicates that DNA rearrangements may also occur 5' to the involved bcl-2 gene. In this case the IgH locus and the bcl-2 gene are found in the order 3' C gamma S gamma/mu JH 5'::5' bcl-2 3' (where C = constant, S = switch, and JH = joining segment of the heavy chain locus), suggesting that an inversion also occurred during the translocation process. The coding regions of the bcl-2 gene, however, are left intact in all cases of follicular lymphoma studied to date.

Bipolar affective disorder in adolescence: a 10-year study

A descriptive study of bipolar affective disorder in adolescent patients, conducted over a 10-year period, is presented. The diagnosis of 30 subjects referred to an adolescent treatment facility of a major teaching hospital was reviewed using DSM-III criteria, and antecedent symptomatology and signs were documented. Common diagnostic features included schizophreniform phenomenology, motoric and vegetative changes, suicidal and inappropriate sexual behaviour and a stormy first year of illness. A positive family history was frequently noted, as was the relevance of various forms of loss as a precipitant of the first episode. Timely recognition and multidisciplinary management, including the use of lithium, are discussed. It appears that the prognosis of bipolar affective disorder in adolescence is better than was previously believed, probably as a result of earlier diagnosis and more frequent recognition.

Anaerobic metabolism of 2-amino-3-methyl-3H-imidazo[4,5-f]quinoline (IQ) by human fecal flora

Incubation of the heterocyclic cooked food mutagen IQ with mixed human fecal microflora under anaerobic conditions yielded 2-amino-3,6-dihydro-3-methyl-7H-imidazo[4,5-f]quinoline-7-one (2) as the major detectable metabolite.

Reliability of the psychosocial axes of DSM-III in an adolescent population

Three psychosocial variables were rated independently by two clinicians for 140 adolescent referrals to a psychiatric unit. Overall, intraclass correlations for DSM-III Axis IV, Axis V and a psychosocial adversity index (PSAI) were respectively 0.44, 0.58 and 0.68. The main source of unreliability is probably the operational definitions, rather than their application by clinicians; indices similar to the PSAI may be preferable.