Bibliometric analysis of aids literature in Latin America and the Caribbean

This work reports on the preliminary results of a bibliometric analysis of AIDS literature, as produced in or about Latin America and the Caribbean for the period 1980–1996. Two international and two regional secondary sources were used in order to obtain comparative analyses regarding for example, comprehensiveness of AIDS literature coverage and local/main frame visibility. Less than 1000 records were retrieved from each of the databases searched. Leading countries in AIDSLINE were Haiti, Brasil, Mexico and Puerto Rico. The distribution by year of publication showed a decrease in Haiti records, from 54 in 1983, to 4 in 1995. The rest of the countries either increased or maintained an average production throughout the years. Regional secondary information sources were less current and comprehensive in the field. Further lines of research are described by the authors.     

High resolution gas chromatographic - mass-spectrometric determination of the flavour composition of basil (Ocimum basilicum L.) cultivated in Finland

High-resolution gas chromatography and mass spectrometry were used to analyse the composition of the volatile oil of basil (Ocimum basilicum L.) cultivated in Finland. Of the 54 compounds identified, seven are now reported for the first time as basil constituents. The effect of growth location, nitrogen fertilizer supply and cultivation under cover vs. open field on the yield and composition of the essential oil is discussed. The increase of total oil production observed under certain cultivation conditions mainly reflects the increased production of certain aroma components rather than all of them. Depending on the chemotype, estragol or eugenol increased the most, whereas linalool production was significantly less affected.[/p]     

Biological and technical variables affecting immunoassay recovery of cytokines from human serum and simulated vaginal fluid: a multicenter study

The increase of proinflammatory cytokines in vaginal secretions may serve as a surrogate marker of unwanted inflammatory reaction to microbicide products topically applied for the prevention of sexually transmitted diseases, including HIV-1. Interleukin (IL)-1beta and IL-6 have been proposed as indicators of inflammation and increased risk of HIV-1 transmission; however, the lack of information regarding detection platforms optimal for vaginal fluids and interlaboratory variation limit their use for microbicide evaluation and other clinical applications. This study examines fluid matrix variants relevant to vaginal sampling techniques and proposes a model for interlaboratory comparisons across current cytokine detection technologies. IL-1beta and IL-6 standards were measured by 12 laboratories in four countries, using 14 immunoassays and four detection platforms based on absorbance, chemiluminescence, electrochemiluminescence, and fluorescence. International reference preparations of cytokines with defined biological activity were spiked into (1) a defined medium simulating the composition of human vaginal fluid at pH 4.5 and 7.2, (2) physiologic salt solutions (phosphate-buffered saline and saline) commonly used for vaginal lavage sampling in clinical studies of cytokines, and (3) human blood serum. Assays were assessed for reproducibility, linearity, accuracy, and significantly detectable fold difference in cytokine level. Factors with significant impact on cytokine recovery were determined by Kruskal-Wallis analysis of variance with Dunn's multiple comparison test and multiple regression models. All assays showed acceptable intra-assay reproducibility; however, most were associated with significant interlaboratory variation. The smallest reliably detectable cytokine differences ( P < 0.05) derived from pooled interlaboratory data varied from 1.5- to 26-fold depending on assay, cytokine, and matrix type. IL-6 but not IL-1beta determinations were lower in both saline and phosphate-buffered saline as compared to vaginal fluid matrix, with no significant effect of pH. The (electro)chemiluminescence-based assays were most discriminative and consistently detected <2-fold differences within each matrix type. The Luminex-based assays were less discriminative with lower reproducibility between laboratories. These results suggest the need for uniform vaginal sampling techniques and a better understanding of immunoassay platform differences and cross-validation before the biological significance of cytokine variations can be validated in clinical trials. This investigation provides the first standardized analytic approach for assessing differences in mucosal cytokine levels and may improve strategies for monitoring immune responses at the vaginal mucosal interface.     

Analysis of the Internet diffusion in the non-profit sector: the social digital divide in Italy

Summary This paper analyzes Internet diffusion among various organizations, based on daily observation of second- level domain name registrations under the “.it”ccTLD. In particular, we analyzed domain names registered by organizations in the non-profit sector.<span style='font-size:12.0pt;mso-ansi-language: HU'>The penetration rate, calculated according to the number of organizations, was computed for various widely separated geographic levels (regions). A concentration analysis was performed in order to determine whether the geographical distribution of Internet use in Italy is less concentrated with respect to both the number of existing institutions and income distribution, suggesting a diffusive effect.<span lang=EN-US style='font-size:12.0pt; mso-ansi-language:EN-US'>Regression analysis was performed using demographic, social, economic and infrastructure indicators. Results show that<span style='font-size:12.0pt;mso-ansi-language:HU'>a “social digital divide”exists, both in terms of geographical distribution (i.e., in macro-areas - Northern, Central, and Southern Italy - and at the regional level) and in terms of the legal status of the organizations, and that this digital divide will probably decrease in the future.     

Oxidative desaturation of α-linolenic,linoleic, and stearic acids by human liver microsomes

The desaturation of stearic, linoleic, and α-linolenic acids by human liver microsomes were studied. The microsomes were isolated from liver biopsies obtained during operations. It was shown that human liver microsomes are able to desaturate 1-¹⁴C-α-linolenic acid to octadeca-6,9,12,15-tetraenoic acid; 1-¹⁴C-linoleic acid to γ-linolenic acid; and 1-¹⁴C-stearic acid to oleic acid in the same system described in the rat. However, the desaturation activity obtained was low compared to other mammals. This effect was attributed to fasting, premedication, or the anaesthesia.     

Design,Synthesis, and Biological Evaluation of Levoglucosenone‐Derived Ras Activation Inhibitors

A panel of new potential Ras ligands was generated by decorating a tricyclic levoglucosenone‐derived scaffold with aromatic moieties. Some members of the panel show in vitro inhibitory activity toward the nucleotide exchange process on Ras and are toxic to some human cancer cell lines.

     

Ultrastructural alterations during embryonic rats' lung development caused by ozone

Ozone (O3) is an oxidizing agent that acts on phospholipids, proteins and sugars of cellular membranes producing free radicals, which cause oxidative damages. The O3 exposure has been used as a model to study oxidative stress, in which the respiratory airways represent the entrance to the organism. In this study, ultrastructural alterations were identified at the bronchiolar level during the intra-uterine lung development, using an O3 exposure model in pregnant rats during 18, 20 and 21 days of gestation. Twelve pregnant Wistar rats, six controls and six exposed to 1 ppm O3 inhalation during 12 h per day, were used. The rats were sacrificed at gestational days 18, 20 and 21; the fetuses were obtained and their lungs dissected. The ultrastructural analysis evidenced swollen mitochondria, cytoplasmic vacuolization of the epithelial cells and structural disorder caused by the oxidative stress. At gestation day 20, flake-off epithelial cells and laminar bodies in the bronchiolar lumen were observed. In the 21-gestation-day group, the mitochondria were edematous and their cristae were disrupted by the damage caused in mitochondrial membranes.     

Metataxonomic and immunological analysis of milk from ewes with or without a history of mastitis

Mastitis is a highly prevalent condition that has a great impact on milk production and animal welfare, and often requires substantial management efforts. For this reason, it is generally considered an important threat to the dairy industry. Many microbial, host, and environmental factors can protect against, predispose to, or influence the development of mastitis. The objective of this work was to characterize the milk microbiota of Manchega ewes, and to compare samples from animals with and without a history of mastitis. We analyzed milk samples from 36 ewes belonging to 2 different farms (18 ewes from each farm) using culture-dependent and culture-independent techniques. We also analyzed several immune compounds to investigate associations of mastitis with 3 main variables: farm; history of mastitis or no mastitis; and parity number. Both culture-dependent and culture-independent techniques showed that ewe milk harbored a site-specific complex microbiota and microbiome. Staphylococcus epidermidis was the main species driving the difference between farm A (where it was the dominant species) and B (where it was not). In contrast, samples from farm B were characterized by the presence of a wide spectrum of other coagulase-negative staphylococci. Some of these species have already been associated with subclinical intramammary infections in ruminants. Of the 10 immune compounds assayed in this study, 3 were related to a history of mastitis [IL-8, IFN-γ, and IFN-gamma-induced protein 10 (IP-10)]. Increases in IL-8 concentrations in milk seemed to be a feature of subclinical mastitis in sheep, and in this study, this immune factor was detected only in samples from ewes with some episodes of mastitis and from the group with the highest somatic cell count. We also observed a positive correlation between the samples with the highest somatic cell count and IFN-γ and IP-10 levels. Our results suggest that these 3 compounds could be used as biomarkers for the negative selection of mastitis-prone animals, particularly when somatic cell count is very high.     

Kinetics and modified clay thermodynamic from the Brazilian amazon region for lead removal

Modified Brazilian smectite-bearing clay samples displayed ability for lead adsorption. The structure modification of smectite were obtained through pillaring process and functionalization with [3-(2-aminoethylamino)propyl]trimethoxysilane. The chemical modification process increases the basal spacing of the natural smectite from 1.354 to 2.364 nm. The Langmuir model was fitted to experimental data in linear regression. Kinetic studies showed an equilibrium adsorption time of 700 min on the modified clay. The experimental data were correlated with two distinct kinetic models were used: (i) external mass transfer diffusion and (ii) intraparticular mass transfer diffusion. However, the intraparticle mass transfer diffusion model gave a better fit to these experimental data. The energetic effects caused by lead interactions were determined through calorimetric titration at the solid-liquid interface and gave a net thermal effect that enabled the calculation of the exothermic values and the equilibrium constant.     

Stable transfection of human β‐1,4N‐acetylgalactosaminyltransferase and α‐2,8‐sialyltransferase cDNAs in C6 rat glioma cells induces modifications in ganglioside metabolism

Ganglioside distribution in cells undergoes deep modifications during physiological and pathological events, possibly depending on the activity of glycosyltransferases involved in their biosynthesis. To understand how the ganglioside pattern can be altered by the selective expression of specific glycosyltransferases, C6 rat glioma cell line was stably transfected with two human glycosyltransferase cDNAs: β ‐1,4N‐acetylgalactosaminyltransferase (GalNAcT) and α ‐2,8‐sialyltransferase (ST‐II). GalNAcT and ST‐II are key enzymes in ganglioside biosynthesis; whereas ST‐II synthesizes GD₃, precursor of the “b” pathway, GalNAcT produces GM₂, GD₂ and asialo‐GM₂ and it is, therefore, involved in “a”, “b” and “asialo” pathways. C6 cells were subjected to three independent transfections: one with a construct containing GalNAcT cDNA, one with a construct containing the ST‐II cDNA, and one with both constructs simultaneously. Whereas control cells present mainly N‐acetyl‐ and N‐glycolyl‐GM₃, selected transfected clones show more complex ganglioside profiles: GalNAcT‐expressing cells are enriched in the “a” series gangliosides, ST‐II‐expressing cells synthesize the “b” series species, cells expressing contemporarily the two glycosyltransferases produce gangliosides of both series. Furthermore, among the selected clones, expression of GalNAcT and ST‐II correlates with changes in the ST‐I and ST‐IV activities, indicating that the switching on of the biosynthetic enzymes we investigated influences the activity of endogenous glycosyltransferases, possibly through the modification of the amount of their substrates or products.