Aspects of Experimental Hepatocarcinogenesis

This article, the first of a series of 5, describes the light and electron microscopical features of early foci of parenchymaI cell hyperplasia which developed in the livers of rats fed the carcinogen p-dimethylaminoazobenzene (butter yellow). The cells in the foci possessed increased numbers of free cytoplasmic ribosomes, prominent perinuclear Golgi bodies and bundles of microfilaments. These features suggested that the cells were not merely regenerative in nature but represented a definite carcinogen-induced proliferative response.S. Afr. Med. J., 48, 698 (1974

Symptomatic Porphyria

The administration of hexachlorobenzene (HCB) to rats for periods up to 67 days resulted in the development of gross cytoplasmic vacuolation and the formation of cytoplasmic inclusions. Some of the inclusions consisted of slender tubular structures about 200 A in diameter. Although it was suspected that the inclusions represented precipitated porphyrins, proof of this could not be obtained. The prior administration of iron to some of the animals before commencing feeding with HCB resulted in a more extensive development of the lesions in the liver, and this could account for the higher levels of excreted porphyrins in the iron-laden animals.S. Afr. Med. J., 48, 1833 (1974)

Construction and characterization of two BAC libraries representing a deep-coverage of the genome of chicory (Cichorium intybus L., Asteraceae)

<p>Abstract</p> <p>Background</p> <p>The Asteraceae represents an important plant family with respect to the numbers of species present in the wild and used by man. Nonetheless, genomic resources for Asteraceae species are relatively underdeveloped, hampering within species genetic studies as well as comparative genomics studies at the family level. So far, six BAC libraries have been described for the main crops of the family, <it>i.e</it>. lettuce and sunflower. Here we present the characterization of BAC libraries of chicory (<it>Cichorium intybus </it>L.) constructed from two genotypes differing in traits related to sexual and vegetative reproduction. Resolving the molecular mechanisms underlying traits controlling the reproductive system of chicory is a key determinant for hybrid development, and more generally will provide new insights into these traits, which are poorly investigated so far at the molecular level in Asteraceae.</p> <p>Findings</p> <p>Two bacterial artificial chromosome (BAC) libraries, CinS2S2 and CinS1S4, were constructed from <it>Hin</it>dIII-digested high molecular weight DNA of the contrasting genotypes C15 and C30.01, respectively. C15 was hermaphrodite, non-embryogenic, and <it>S</it>₂<it>S</it>₂for the <it>S</it>-locus implicated in self-incompatibility, whereas C30.01 was male sterile, embryogenic, and <it>S</it>₁<it>S</it>₄. The CinS2S2 and CinS1S4 libraries contain 89,088 and 81,408 clones. Mean insert sizes of the CinS2S2 and CinS1S4 clones are 90 and 120 kb, respectively, and provide together a coverage of 12.3 haploid genome equivalents. Contamination with mitochondrial and chloroplast DNA sequences was evaluated with four mitochondrial and four chloroplast specific probes, and was estimated to be 0.024% and 1.00% for the CinS2S2 library, and 0.028% and 2.35% for the CinS1S4 library. Using two single copy genes putatively implicated in somatic embryogenesis, screening of both libraries resulted in detection of 12 and 13 positive clones for each gene, in accordance with expected numbers.</p> <p>Conclusions</p> <p>This indicated that both BAC libraries are valuable tools for molecular studies in chicory, one goal being the positional cloning of the <it>S</it>-locus in this Asteraceae species.</p

Symptomatic Porphyria

A study has been made of 7 alcoholic and 2 non-alcoholic patients with symptomatic porphyria. Siderosis (mild or absent in most cases), focal fatty change and lipofuscin pigmentation were noted on light microscopy while ultrastructural study revealed that focal cellular lysis was unexpectedly common. Unidentified cytoplasmic inclusions (possibly porphyrins) were present in 3 cases. It was concluded that increased synthesis and storage of porphyrins in the liver could lead to some cytoplasmic damage, but that alcoholic excess probably accounts for the majority of the hepatocellular abnormalities.S. Afr. Med. J., 48, 1803 (1974