Human HepG2 and Rat Fao Hepatic-Derived Cell Lines Show Different Responses to Ciprofibrate, a Peroxisome Proliferator: Analysis by Flow Cytometry

Peroxisome proliferators, and especially hypolipidemic drugs such as ciprofibrate, are known to be hepatocarcinogens in rodents, but their effect in humans is controversial. In an attempt to investigate the effects of ciprofibrate at a cellular level, the analysis of individual whole cells was performed by flow cytometry on samples from two hepatic-derived cell lines: the rat Fao cell line and the human HepG2 cell line. The increase of light scatter signals in rat Fao cells treated for 3 days with ciprofibrate at 250 μMwas related to modifications of intrinsic cellular parameters, such as size and cytoplasmic granularity. Conversely, no variations appeared in human HepG2-treated cells. Moreover, the study of the cell cycle distribution of asynchronously growing cells showed an increase in the percentage of proliferative cells in Fao-treated cells, but not in HepG2-treated cells. In order to give a simultaneous assessment of changes in cellular parameters and cell metabolism, these flow cytometric experiments were completed with the measurements of the palmitoyl–CoA oxidase activity, used as a marker of peroxisome proliferation. The cellular modifications in the rat Fao cell line were accompanied by a great increase in this enzymatic activity, whereas the human HepG2 cell line, which failed to exhibit changes of cytometric data, presented no, or weak, increase in this oxidase activity. The cellular modifications observed in the rat Fao cell line may be related to the well-known hepatocarcinogenicity of ciprofibrate in rodents, whereas the absence of response of HepG2 cells is in favor of the noncarcinogenicity of this drug in humans. This report validates another methodological approach for the investigation of the safety of peroxisome proliferators in humans.     

The microbiological fate of polycyclic aromatic hydrocarbons: carbon and oxygen balances for bacterial degradation of model compounds

A series of pure bacterial strains belonging mainly to theRhodococcus andPseudomonas genera were grown on one of the following polycyclic aromatic hydrocarbons (PAH) supplied as sole carbon and energy source: naphthalene, fluorene, phenanthrene, anthracene, fluoranthene and pyrene. In each case, a quantitative evaluation of the carbon repartition of the PAH degraded into CO₂, biomass and water-soluble metabolites was carried out. In addition, the kinetics of oxygen consumption and of water-soluble metabolite accumulation during PAH biodegradation was followed with respirometric equipment. Satisfactory carbon balances were obtained and the data correlated well with oxygen consumption values. The results show that growth on PAH presents high mineralization yields (from 56% to 77% of carbon) and sizeable production of biomass (from 16% to 35% of carbon) and limited but significant accumulation of metabolites (from 5% to 23% of carbon). The mineralization yields were higher and biomass yields lower in the case of higher PAH. Some differences between strains were also observed.     

A Second Gene for Cerulean Cataracts Maps to the β Crystallin Region on Chromosome 22

Congenital cataracts are one of the most common major eye abnormalities and often lead to blindness in infants. At least a third of all cases are familial. Within this group, highly penetrant, autosomal dominant forms of congenital cataracts (ADCC) are most common. ADCC is a genetically heterogeneous group of disorders, in which at least eight different loci have been identified for nine clinically distinct forms. Among these, Armitageet al.(Nature Genet.9: 37–40, 1995) mapped a gene for cerulean blue cataracts to chromosome 17q24. Bodkeret al.(Am. J. Med. Genet.37: 54–59, 1990) described a large family with cerulean blue cataracts, in which the affected daughter of affected first cousins was presumed to be homozygous for the purported gene. We report linkage in this family to the region on chromosome 22q that includes two β crystallin genes (CRYBB2, CRYBB3) and one pseudogene (CRYBB2P1). The affected female in question is homozygous at all markers.     

Shifting Narratives and Mutable Meanings

In and Out of Africa . 1993. 59 minutes, color. A film by Ilisa Barbash and Lucien Taylor. For information contact University of California Extension Center for Media and Independent Learning, 2000 Center Street, Fourth Floor, Berkeley, CA 94704, 510–642–0460.     

Inhibition of cuticular lipid synthesis and its effect on insect survival

A new approach to insect control—using sodium trichloroacetate (NaTCA) to inhibit synthesis of the hydrophobic cuticular lipids that protect insects from dehydration—was tested on Triatoma infestans. In vivo and in vitro studies of incorporation of radioactive precursors showed diminished cuticular hydrocarbon synthesis after NaTCA treatment. Thin layer chromatography and scanning electron microscopy showed disruption of the cuticular lipid layer of NaTCA-treated insects, which also have increased mortality and altered molting cycles. NaTCA treatment enhanced the penetration and increased the lethality of a contact insecticide. © 1994 Wiley-Liss, Inc.     

Agave studies in Yucatan,Mexico. II. Nutritional value of the inflorescence peduncle and incipient domestication

Recent ethnobotanical exploration of henequen (Agave fourcroydes) in the Peninsula of Yucatan, Mexico, finds that inflorescence peduncles are used as emergency food and in the preparation of a fermented drink. Bromatological analysis and determination of total carbohydrates were made for the two length classes (ca. 3.30 m and ca. 0.60 m) which are consumed. The analysis of both the cultivated plant and its putative wild ancestor (Agave angustifolia) suggests that utilization of the inflorescence peduncles as food may have been involved in the initial stages of the history of its evolution under artificial selection, because the wild and the cultivated plants have similar palatability. The subsequent agricultural prevalence of annual crop species in the region was possibly responsible for the abandonment of henequen in the local diet. No significant differences are observed between the bromatological and total carbohydrate values of domesticated and wild plants. The preference for small inflorescence peduncles as a vegetable is a consequence of its significantly minor content of raw fiber and its larger content of total carbohydrates. As a fermented drink, longer peduncles are preferred because they provide more substrate material and because fiber can be eliminated by filtering. This agricultural byproduct, almost totally wasted, has potential value as a source of carbohydrates and raw fiber.     

Green mass aggregations of Gyrodinium cf. aureolum Hulburt in the Ria of Pontevedra (north-west Spain)

In this paper we report a bloom of Gyrodinium cf. aureolum occurringin an estuary of the north-west coast of Spain. It was sampledin late August 1989, in shallow waters 2 m deep in the Ria ofPontevedra. Its temperature was 19.5°C and salinity 35     

Molecular modelling of the photoconduction mechanism by charged solitons intrans-polyacetylene: I

It is possible to rationalize the different steps involved in the photoconductivity observed intrans-polyacetylene (t-PA) in terms of a simple chemical model. The interchain electron transfer (IET) and the intrachain polaron capture by neutral solitons proposed by Orensteinat al. may be represented within a simple molecular orbital (MO) picture. An efficiency index for the IET is proposed in terms of the binding energy of the charged polarons and of the electronic chemical potential. The predictive power of the efficiency index is analyzed in the context of the global softness concept. An MO protocol is described to obtain estimates of the IET hopping probabilities.