A genetic model for undifferentiated cell tumor formation: similar tumors formed by different cell lines transformed by the E1A oncogene

The activation of oncogenes and the mutation/deletion of suppressor genes may be involved in tumor heterogeneity. In an attempt to study tumor heterogeneity, we transformed cell lines from epithelial (PAM 212), mesenchymal (NIH-3T3), or melanocytic origin (L-BIOBR) with the wild type E1a oncogene. To make the cell lines tumorigenic, cells were infected with Harvey sarcoma virus carrying the v-H-ras oncogene. The transformed cells were injected into nude mice and the tumors studied by optical and electron microscopy. The tumors formed by v-H-ras-transformed cells consisted of epitheliod melanomas, spindle cells sarcomas and poorly-differentiated carcinomas, depending on the cell of origin. In contrast, the tumors obtained from cells also carrying the E1a oncogene showed a predominant small and undifferentiated cell pattern regardless of the cell of origin. We conclude that the E1a oncogene products induce a negative control of differentiation, independent of the cell type, and that tumors formed by cells carrying the E1a oncogene display an undifferentiated cell pattern.     

The covariation of common psychosomatic symptoms among children from socio-economically differing residential areas. An epidemiological study

Psychosomatic symptoms among children are believed to be commonplace. In this investigation by questionnaire, 47% of 1333 schoolchildren reported one or several symptoms, such as recurrent abdominal pain, headache, chest pains, loss of appetite and disturbances in bowel function. Coexistence of such symptoms was considerable and if a child had one of these, the probability that it would have one or more other symptoms was significantly increased. This correlation may strengthen both the suspicion that these symptoms are often psychosomatic and the idea that they have common CNS origin. There were appreciable differences in the frequency of the symptoms, between children at the more socially stable schools and schools with social problems. In the latter, the frequencies of symptoms differed between Swedish and immigrant children, which was not the case in the more socially stable schools.     

Seroepidemiologic indicators for the evaluation of campaigns for the control of foot-and-mouth disease

A sero-epidemiological survey was conducted in two districts in Argentina between 1993 and 1995, to provide additional information on the epidemiology of foot and mouth disease (FMD) in Argentina and to assess the level of immunity in cattle populations, and the circulation of FMD virus. As part of the final stage of this survey, a comparison was made of the results obtained by the enzyme-linked immunosorbent assay (ELISA) and agar gel immunodiffusion techniques. Levels of population immunity against the four types of virus included in the vaccine increased progressively during the period of the survey until, in 1995, at the end of the vaccination period, the percentage of animals possessing adequate levels of protection was approximately 77% in yearlings, and more than 94% in cattle over one year old. During the three-year study, there was a clear tendency for viral activity to diminish, until in 1995 when between 3% and 0.6% were positive to the agar gel immunodiffusion test for the antigen associated with viral infection. By contrast, the ELISA detected antibody in about five times as many animals. The authors show how the increase in the level of population immunity was accompanied by a fall in viral activity.     

Shotcrete for underground support: a state-of-the-art report with focus on steel-fibre reinforcement

This paper reviews current trends in shortcreting, primarily based on the Status Report of a Working Group of the International Tunneling Association and the most recent U.S. Engineering Foundation conference on the theme (held in Uppsala, Sweden, in 1990). Of special interest is the increasing use of fibre reinforcement, which implies increased safety and substantial cost savings. The need for scientific collaboration and exchange of ideas between concrete and rock mechanics specialists is emphasized as a tool for a better understanding of the support behaviour of shotcrete linings.     

Cellular UDP-glucose deficiency caused by a single point mutation in the UDP-glucose pyrophosphorylase gene

We previously isolated a mutant cell that is the only mammalian cell reported to have a persistently low level of UDP-glucose. In this work we obtained a spontaneous revertant whose UDP-glucose level lies between those found in the wild type and the mutant cell. The activity of UDP-glucose pyrophosphorylase (UDPG:PP), the enzyme that catalyzes the formation of UDP-glucose, was in the mutant 4% and in the revertant 56% of the activity found in the wild type cell. Sequence analysis of UDPG: PP cDNAs from the mutant cell showed one missense mutation, which changes amino acid residue 115 from glycine to aspartic acid. The substituted glycine is located within the largest stretch of strictly conserved residues among eukaryotic UDPG:PPs. The analysis of the cDNAs from the revertant cell indicated the presence of an equimolar mixture of the wild type and the mutated mRNAs, suggesting that the mutation has reverted in only one of the alleles. In summary, we demonstrate that the G115D substitution in the Chinese hamster UDPG:PP dramatically impairs its enzymatic activity, thereby causing cellular UDP-glucose deficiency.     

Organizational determinants of IT adoption in the pharmaceutical distribution sector

The aim of this paper is to propose new organizational factors that might explain the differences in the extent and the speed of IT adoption. With this in mind, we carried out an analysis of 16 cases in the pharmaceutical distribution sector in Spain. The results indicate that there are certain intangible assets that favour the introduction and development of IT. Among these are a frank and fluid communication between departments and members of the organization, low levels of conflict, the explicit support of top management towards IT adoption and learning and creative skills of IT-staff. In addition to these factors, we found others that we propose as catalysts of IT adoption. Among these we might mention the special relationship between the member-clients and the company in the case of cooperative firms.     

Effect of sulphate removal on the surface texture and acid-base properties of TiO2 (anatase)

Commercial anatase containing an appreciable amount of sulphur has been treated for sulphur removal by calcination at increasing temperatures or soaking with aqueous NaOH solutions. It has been found that both methods are active for sulphur removal, but the first one also leads to a sharp sintering of the titania particles. On the other hand, treatment with NaOH_aq leads to incorporation of sodium cations. Both treatments lead also to changes in surface acidity, as measured by Fourier transform infrared (FT-IR) monitoring of pyridine adsorption.     

The use of natural essential oils as antimicrobial solutions in paper packaging. Part II

We have assessed the antimicrobial, vapor-phase activity of the following natural essential oils (EOs) when used in paraffin-based “active coatings” for paper packaging materials intended to come into contact with foods: clove (Sygzium aromaticum), cinnamon (Cinnamomum zeylanicum), and oregano (Origanum vulgare) EOs, and cinnamaldehyde-enriched cinnamon EO. To our knowledge, this is the first time that such an approach has been presented for consideration by the scientific community.