Positive regulation of the peroxisomal beta-oxidation pathway by fatty acids through activation of peroxisome proliferator-activated receptors (PPAR).

Peroxisome proliferators regulate the transcription of genes by activating ligand-dependent transcription factors, which, due to their structure and function, can be assigned to the superfamily of nuclear hormone receptors. Three such peroxisome proliferator-activated receptors (PPAR alpha, beta, and gamma) have been cloned in Xenopus laevis. Their mRNAs are expressed differentially; xPPAR alpha and beta but not xPPAR gamma are expressed in oocytes and embryos. In the adult, expression of xPPAR alpha and beta appears to be ubiquitous, and xPPAR gamma is mainly observed in adipose tissue and kidney. Immunocytochemical analysis revealed that PPARs are nuclear proteins, and that their cytoplasmic-nuclear translocation is independent of exogenous activators. A target gene of PPARs is the gene encoding acyl-CoA oxidase (ACO), which catalyzes the rate-limiting step in the peroxisomal beta-oxidation of fatty acids. A peroxisome proliferator response element (PPRE), to which PPARs bind, has been identified within the promoter of the ACO gene. Besides the known xenobiotic activators of PPARs, such as hypolipidemic drugs, natural activators have been identified. Polyunsaturated fatty acids at physiological concentrations are efficient activators of PPARs, and 5,8,11,14-eicosatetraynoic acid (ETYA), which is the alkyne homolog of arachidonic acid, is the most potent activator of xPPAR alpha described to date. Taken together, our data suggest that PPARs have an important role in lipid metabolism.

How geographic distance and depth drive ecological variability and isolation of demersal fish communities in an archipelago system (Cape Verde, Eastern Atlantic Ocean)

Cape Verde is a tropical oceanic ecosystem, highly fragmented and dispersed, with islands physically isolated by distance and depth. To understand how isolation affects the ecological variability in this archipelago, we conducted a research project on the community structure of the 18 commercially most important demersal fishes. An index of ecological distance based on species relative dominance (Di) is developed from Catch Per Unit Effort, derived from an extensive database of artisanal fisheries. Two ecological measures of distance between islands are calculated: at the species level, DDi, and at the community level, DD (sum of DDi). A physical isolation factor (Idb) combining distance (d) and bathymetry (b) is proposed. Covariance analysis shows that isolation factor is positively correlated with both DDi and DD, suggesting that Idb can be considered as an ecological isolation factor. The effect of Idb varies with season and species. This effect is stronger in summer (May to November), than in winter (December to April), which appears to be more unstable. Species react differently to Idb, independently of season. A principal component analysis on the monthly (DDi) for the 12 islands and the 18 species, complemented by an agglomerative hierarchical clustering, shows a geographic pattern of island organization, according to Idb. Results indicate that the ecological structure of demersal fish communities of Cape Verde archipelago, both in time and space, can be explained by a geographic isolation factor. The analytical approach used here is promising and could be tested in other archipelago systems.

Primary Health Care from the perception of women living in a rural area

AbstractOBJECTIVEUnderstanding the perception of women living in a rural area about the actions and services of Primary Health Care (PHC) in a municipality of southern Brazil, which is the only one regarded as predominantly rural.METHODA descriptive study of qualitative approach, carried out with women who lived in the countryside and required health services in the 15 days prior to collection.RESULTSThe results registered low fidelity to PHC attributes, focusing its functional axis on sickness, transforming the unit into small points of emergency care and a bureaucratic place where patients are referred to other types of services. The quality of service offered is compromised to offering quick, fragmented and unequal treatment in the rural context.CONCLUSIONThe findings of this study highlight the need for greater efforts in order to adequate the new care model in the development of appropriate actions as designated by PHC in the rural context studied.

An external site controls closing of the epithelial Na+ channel ENaC.

Members of the ENaC/degenerin family of ion channels include the epithelial sodium channel (ENaC), acid-sensing ion channels (ASICs) and the nematode Caenorhabditis elegans degenerins. These channels are activated by a variety of stimuli such as ligands (ASICs) and mechanical forces (degenerins), or otherwise are constitutively active (ENaC). Despite their functional heterogeneity, these channels might share common basic mechanisms for gating. Mutations of a conserved residue in the extracellular loop, namely the 'degenerin site' activate all members of the ENaC/degenerin family. Chemical modification of a cysteine introduced in the degenerin site of rat ENaC (betaS518C) by the sulfhydryl reagents MTSET or MTSEA, results in a approximately 3-fold increase in the open probability. This effect is due to an 8-fold shortening of channel closed times and an increase in the number of long openings. In contrast to the intracellular gating domain in the N-terminus which is critical for channel opening, the intact extracellular degenerin site is necessary for normal channel closing, as illustrated by our observation that modification of betaS518C destabilises the channel closed state. The modification by the sulfhydryl reagents is state- and size-dependent consistent with a conformational change of the degenerin site during channel opening and closing. We propose that the intracellular and extracellular modulatory sites act on a common channel gate and control the activity of ENaC at the cell surface.

Meliponini neotropicais: o gênero Partamona Schwarz, 1939 (Hymenoptera, Apidae, Apinae) - bionomia e biogeografia

This work, dedicated to the study of nesting habits of the species of the Neotropical genus Partamona Schwarz, is a sequence to the taxonomic revision recently published elsewhere. A total of 214 nests and nest aggregations of 18 species [Partamona epiphytophila Pedro & Camargo, 2003; P. testacea (Klug, 1807); P. mourei Camargo, 1980; P. vicina Camargo, 1980; P. auripennis Pedro & Camargo, 2003; P. combinata Pedro & Camargo, 2003; P. chapadicola Pedro & Camargo, 2003; P. nhambiquara Pedro & Camargo, 2003; P. ferreirai Pedro & Camargo, 2003; P. pearsoni (Schwarz, 1938); P. gregaria Pedro & Camargo, 2003; P. batesi Pedro & Camargo, 2003; P. ailyae Camargo, 1980; P. cupira (Smith, 1863); P. mulata Moure in Camargo, 1980; P. seridoensis Pedro & Camargo, 2003; P. criptica Pedro & Camargo, 2003; P. helleri (Friese, 1900)] were studied , including data about habitat, substrate, structural characteristics, construction materials and behavior. The descriptions of the nests are illustrated with 48 drawings. Partial data of the nests of P. bilineata (Say, 1837), P. xanthogastra Pedro & Camargo, 1997, P. orizabaensis (Strand, 1919), P. peckolti (Friese, 1901), P. aequatoriana Camargo, 1980, P. musarum (Cockerell, 1917) and P. rustica Pedro & Camargo, 2003 are also presented. Nests of P. grandipennis (Schwarz, 1951), P. yungarum Pedro & Camargo, 2003, P. subtilis Pedro & Camargo, 2003, P. vitae Pedro & Camargo, 2003, P. nigrior (Cockerell, 1925), P. sooretamae Pedro & Camargo, 2003 and P. littoralis Pedro & Camargo, 2003 are unknown. The species of Partamona build notable nest entrance structures, with special surfaces for incoming / exiting bees; some of them are extremely well-elaborated and ornamented, serving as flight orientation targets. All species endemic to western Ecuador to Mexico with known nesting habits (P. orizabaensis, P. peckolti, P. xanthogastra, P. bilineata, P. aequatoriana and P. musarum) build their nests in several substrates, non-associated with termitaria, such as cavities and crevices in walls, among roots of epiphytes and in bases of palm leaves, in abandoned bird nests, under bridges, and in other protected places, except P. peckolti that occasionally occupies termite nests. In South America, on the eastern side of the Andes, only P. epiphytophila and P. helleri nest among roots of epiphytes and other substrates, non-associated with termitaria. All other species studied (P. batesi, P. gregaria, P. pearsoni, P. ferreirai, P. chapadicola, P. nhambiquara, P. vicina, P. mourei, P. auripennis, P. combinata, P. cupira, P. mulata, P. ailyae, P. seridoensis, P. criptica and P. rustica) nest inside active termite nests, whether epigeous or arboreous. The only species that builds obligate subterranean nests, associated or not with termite or ant nests (Atta spp.) is P. testacea. Nests of Partamona have one vestibular chamber (autapomorphic for the genus) closely adjacent to the entrance, filled with a labyrinth of anastomosing pillars and connectives, made of earth and resins. One principal chamber exists for food and brood, but in some species one or more additional chambers are filled with food storage pots. In nests of P. vicina, there is one atrium or "false nest", between the vestibule and the brood chamber, which contains involucral sheaths, cells and empty pots. All structures of the nest are supported by permanent pillars made of earth and resins (another autapomorphy of the genus). The characters concerning nesting habits were coded and combined with morphological and biogeographic data, in order to hypothesize the evolutive scenario of the genus using cladistic methodology. The phylogenetic hypothesis presented is the following: (((((P. bilineata (P. grandipennis, P. xanthogastra)) (P. orizabaensis, P. peckolti)) (P. aequatoriana, P. musarum)) P. epiphytophila, P. yungarum, P. subtilis, P. vitae) (((((P. testacea (P. mourei, P. vicina)) (P. nigrior (P. auripennis, P. combinata))) (P. ferreirai (P. pearsoni (P. gregaria (P. batesi (P. chapadicola, P. nhambiquara)))))) ((((P. ailyae, P. sooretamae) P. cupira, P. mulata) P. seridoensis) P. criptica, P. rustica, P. littoralis)) P. helleri))). One area cladogram is presented. Dates of some vicariance / cladogenesis events are suggested. For bilineata / epiphytophila group, which inhabits the Southwestern Amazonia and the Chocó-Mexican biogeographical components, the origin of ancestral species is attributed to the Middle Miocene, when the transgressions of the Maracaibo and Paranense seas isolated the tropical northwestern South America from the eastern continental land mass. The next cladogenic event in the history of the bilineata / epiphytophila group is attributed to the Plio-Pleistocene, when the Ecuadorian Andes reached more than 3000 m, and the ancestral species was fragmented in two populations, one occupying the western Andes (ancestral species of the bilineata subgroup) and other the southwestern Amazon (ancestral species of the epiphytophila subgroup). Other aspects of the history of Partamona are also discussed.

Quasi-integration in less-than-truckload trucking

This work studies the organization of less-than-truckload trucking from a contractual point of view. We show that the huge number of owner-operators working in the industry hides a much less fragmented reality. Most of those owner-operators are quasi-integrated in higher organizational structures. This hybrid form is generally more efficient than vertical integration because, in the Spanish institutional environment, it lessens serious moral hazard problems, related mainly to the use of the vehicles, and makes it possible to reach economies of scale and density. Empirical evidence suggests that what leads organizations to vertically integrate is not the presence of such economies but hold-up problems, related to the existence of specific assets. Finally, an international comparison hints that institutional constraints are able to explain differences in the evolution of vertical integration across countries.

Three essays on organizations and their external environment

Abstract: The literature on the various links between organizations and their external environment is very extensive and fragmented. This thesis is comprised of three separate essays, each examining specific research questions related to these links. The first essay deals with the notion of industry life cycle and how the geographical concentration of an industry is linked to the particular life cycle stage in which the industry finds itself. The aim of this first essay is firstly to verify if the evolution of the Swiss hotel industry fits some of the stylized facts of the industry life cycle. The second aim is to verify if there is evidence of geographical clustering of the hotel industry, and by extension of tourism. The third aim is to verify a hypothesis that industry decline manifests itself mainly by company closures in decentralized locations. The importance for organizational survival and performance of adapting and reacting to environmental changes has long been ascertained. This adaptation requires managers, under conditions of uncertainty, to identify relevant changes in their external environment and to interpret the possible effects of those changes on their organization. Furthermore, it requires finding and adopting organizational responses in reaction to the environmental changes. The second essay explores how managers perceive their environment by reporting the results of two workshops held with managers from the European hotel industry. In the third essay we examine in more detail the role of uncertainty in the interpretation by executives of environmental changes. We integrate existing theories of interpretation and uncertainty into one framework, which we then test using national survey data from the hotel industry. In all three essays we are able to provide some evidence to support our main hypotheses, but.also make suggestions far further research into the topics examined.

Ejaculation failure on the day of oocyte retrieval for IVF: case report.

Unexpected ejaculation failure on the day of oocyte retrieval for IVF occurs once or twice a year in our Reproductive Medicine Unit, where approximately 500 oocyte retrievals are performed each year. Two clinical situations which occurred in 2001 are presented. In the first case, sperm were finally obtained by epididymal aspiration and resulted in the fertilization of five oocytes by ICSI. The transfer of two fresh embryos did not result in a pregnancy and the three supernumerary zygotes were cryopreserved. The male patient presented an anxio-depressive episode necessitating psychiatric hospitalization 1 week after the oocyte retrieval. In the second case, no sperm were obtained and the four oocytes were therefore lost. The couple went through a crisis in their relationship and tried another cycle of IVF 10 months later, after the preventive cryopreservation of a sperm sample. On the day of oocyte retrieval the patient was unable to produce a fresh sample but three zygotes were obtained through ICSI using the back-up cryopreserved sperm. Two embryos were transferred but no pregnancy ensued. The clinical decision-making processes for these two cases are described, as well as the measures employed to help prevent these unfortunate situations.

Fanconi-Bickel syndrome and autosomal recessive proximal tubulopathy with hypercalciuria (ARPTH) are allelic variants caused by GLUT2 mutations.

CONTEXT: Many inherited disorders of calcium and phosphate homeostasis are unexplained at the molecular level. OBJECTIVE: The objective of the study was to identify the molecular basis of phosphate and calcium abnormalities in two unrelated, consanguineous families. PATIENTS: The affected members in family 1 presented with rickets due to profound urinary phosphate-wasting and hypophosphatemic rickets. In the previously reported family 2, patients presented with proximal renal tubulopathy and hypercalciuria yet normal or only mildly increased urinary phosphate excretion. METHODS: Genome-wide linkage scans and direct nucleotide sequence analyses of candidate genes were performed. Transport of glucose and phosphate by glucose transporter 2 (GLUT2) was assessed using Xenopus oocytes. Renal sodium-phosphate cotransporter 2a and 2c (Npt2a and Npt2c) expressions were evaluated in transgenically rescued Glut2-null mice (tgGlut2-/-). RESULTS: In both families, genetic mapping and sequence analysis of candidate genes led to the identification of two novel homozygous mutations (IVS4-2A>G and R124S, respectively) in GLUT2, the gene mutated in Fanconi-Bickel syndrome, a rare disease usually characterized by renal tubulopathy, impaired glucose homeostasis, and hepatomegaly. Xenopus oocytes expressing the [R124S]GLUT2 mutant showed a significant reduction in glucose transport, but neither wild-type nor mutant GLUT2 facilitated phosphate import or export; tgGlut2-/- mice demonstrated a profound reduction of Npt2c expression in the proximal renal tubules. CONCLUSIONS: Homozygous mutations in the facilitative glucose transporter GLUT2, which cause Fanconi-Bickel syndrome, can lead to very different clinical and biochemical findings that are not limited to mild proximal renal tubulopathy but can include significant hypercalciuria and highly variable degrees of urinary phosphate-wasting and hypophosphatemia, possibly because of the impaired proximal tubular expression of Npt2c.

Abnormal balance between proliferation and apoptotic cell death in fibroblasts derived from keloid lesions.

A new culture model was developed to study the role of proliferation and apoptosis in the etiology of keloids. Fibroblasts were isolated from the superficial, central, and basal regions of six different keloid lesions by using Dulbecco's Modified Eagle Medium containing 10% fetal calf serum as a culture medium. The growth behavior of each fibroblast fraction was examined in short-term and long-term cultures, and the percentage of apoptotic cells was assessed by in situ end labeling of fragmented DNA. The fibroblasts obtained from the superficial and basal regions of keloid tissue showed population doubling times and saturation densities that were similar to those of age-matched normal fibroblasts. In contrast, the fibroblasts from the center of the keloid lesions showed significantly reduced doubling times (25.9 +/- 6.3 hours versus 43.5 +/- 6.3 hours for normal fibroblasts) and reached higher cell densities. In long-term culture, central keloid fibroblasts formed a stratified three-dimensional structure, contracted the self-produced extracellular matrix, and gave rise to nodular cell aggregates, mimicking the formation of keloid tissue. Apoptotic cells were detected in both normal and keloid-derived fibroblasts, but their numbers were twofold higher in normal cells compared with all keloid fibroblasts. To examine whether apoptosis mediates the therapeutic effect of ionizing radiation on keloids, the cells were exposed to gamma rays at a dose of 8 Gy. Under these conditions, a twofold increase in the population of apoptotic cells was detected. These results indicate that the balance between proliferation and apoptosis is impaired in keloid fibroblasts, which could be responsible for the formation of keloid tumors. The results also suggest that keloids contain at least two different fibroblast fractions that vary in growth behavior and extracellular matrix metabolism.

Adiponectin isoform distribution in serum and in follicular fluid of women undergoing treatment by ICSI.

Adiponectin is an adipokine, present in the circulation in comparatively high concentrations and different molecular weight isoforms. For the first time, the distribution of these isoforms in serum and follicular fluid (FF) and their usefulness as biological markers for infertility investigations was studied. In vitro study. University based hospital. Fifty-four women undergoing intracytoplasmic sperm injection (ICSI). Oocytes were retrieved, fertilized in vitro using ICSI, and the resulting embryos transferred. Serum was collected immediately prior to oocyte retrieval. Adiponectin isoforms (high molecular weight (HMW), medium and low molecular weight) were determined in serum and FF. Total adiponectin and the different isoform levels were compared with leptin and ovarian steroid concentrations. Adiponectin isoforms in serum and FF. Adiponectin isoform distribution differed between serum and FF; the HMW fraction made up half of all adiponectin in the serum but only 23.3% in the FF. Total and HMW adiponectin in both serum and FF correlated negatively with the body mass index and the concentration of leptin. No correlations were observed for total adiponectin or its isoforms with estradiol, progesterone, anti-Mullerian hormone, inhibin B, or the total follicle stimulating hormone (FSH) dose administered during the ovarian stimulation phase. This study shows for the first time that adiponectin isoform distribution varies between the serum and FF compartments in gonadotropin stimulated patients. A trend towards higher HMW adiponectin serum levels in successful ICSI cycles compared to implantation failures was observed; studies with larger patient groups are required to confirm this observation.

El nuevo método para la determinación de la fecundidad de la Sardina peruana (Sardinops sagax)

La fecundidad de la sardina peruana, Sardinops sagax, fue determinada por primera vez contando el número de ovoci­tos hidratados. El análisis de varianza mostró que las diferencias entre submuestras tomadas de diferentes áreas del ovario fueron en unos casos significativas al nivel del 5%. Estas diferencias son insignificantes a nivel de la población tomando en consideración la alta variación de la fecundidad entre diferentes hembras del mismo peso.

Fecundidad parcial de Caballa del Perú (Scomber japonicus peruanus)

Un nuevo método, el conteo de ovocitos hidratados, se aplica por primera vez para determinar la fecundidad de la caballa peruana (Scomber Japonicus peruanus) . En febrero de 1985, la fecundidad relativa media fue 278 huevos por gramo de hembra y la fecundidad parcial media de la muestra fue 78,174 huevos por hembra. Se muestra que la caballa del Perú es un desovador múltiple.

Diversity of the euglossine bee community (Hymenoptera, Apidae) of an Atlantic Forest remnant in southeastern Brazil

Diversity of the euglossine bee community (Hymenoptera, Apidae) of an Atlantic Forest remnant in southeastern Brazil. Euglossine bees, attracted to scent baits of cineole, eugenol and vanillin, were collected with entomological nets, from December 1998 to November 1999. Samplings were carried out once a month simultaneously by two collectors positioned in two different sites in an Atlantic Forest remnant in northeastern São Paulo state, Brazil. A total of 859 male euglossine bees, belonging to 13 species and four Euglossini genera were collected. Of the total sample, 506 (12 species) males were captured at site A and 353 (10 species) were collected at site B.In both sites, Euglossa pleosticta Dressler, 1982 was the most abundant species (45.79%), followed by Eulaema nigrita Lepeletier, 1841 (20.79%). The results of this study supply new information about the diversity of orchid bee fauna in Atlantic Forest remnants as well as show that more than one site is needed to sample these bees in a fragmented landascape.

Track analysis of the Neotropical Entimini (Coleoptera: Curculionidae: Entiminae)

Track analysis of the Neotropical Entimini (Coleoptera, Curculionidae, Entiminae). Distributional patterns of the species belonging to the tribe Entimini from the Neotropical region were analyzed. Based on a track analysis of 22 species of Entimus, Rhigus, and Phaedropus, for which distributional data were available, two generalized tracks were found. One is located in northern Brazil, corresponding to the Amazonian subregion, and is determined by Phaedropus candidus and Rhigus speciosus. The other is located in southern Brazil, corresponding to the Parana subregion, and is determined by Entimus imperialis, E. excelsus, Phaedropus togatus, Rhigus dejeanii, R. faldermanni, R. horridus, R. lateritus, R. nigrosparsus, and R. tribuloides. The development of the Chacoan subregion is hypothesized to have been the dynamic vicariant event that fragmented the former Amazonian-Parana forest.