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PubMed2002

Radon in groundwaters from Guarany aquifer, South America: environmental and exploration implications.

Groundwater and sandstone samples were analyzed for radon in Guarany aquifer, Paraná sedimentary basin, South America. The dissolved radon ranged between 3 and 3303pCi/l, being lognormally distributed, with a modal value of 1315pCi/l, and a median value of 330pCi/l. 222Rn leakage experiments for sandstones yielded a theoretical value of 1390pCi/l for 222Rn in water, showing that theoretical modeling can reliably be used to interpret laboratory and field data.

Journal Article↗

PubMed1990

Incidence, epidemiology and control of bovine virus diarrhoea virus in South America.

Outbreaks of diarrhoea associated with mucosal erosions of the mouth, tongue and digestive tract, clinically diagnosed as bovine virus diarrhoea-mucosal disease (BVD-MD), have been reported in Argentina and Brazil since the 1960's. However, primary isolation of the virus of BVD-MD is fairly recent, occurring in 1974 for Brazil, 1984 for Argentina, 1985 for Chile and 1981 for Colombia. In Argentina both cytopathogenic and non-cytopathogenic BVD virus strains have been identified. Elsewhere in South America this differentiation does not seem to have been carried out. Serological surveys have confirmed the existence of BVD virus infection in six countries (Argentina, Brazil, Chile, Colombia, Peru and Uruguay), with an incidence rate ranging between 37 and 77% of cattle in the areas surveyed. Diarrhoea in calves between 3 and 18 months of age, often associated with mucosal erosions, has been the most commonly observed syndrome. In some cases an upper respiratory tract involvement was described. In one epizootic, in the Sabana de Bogota plateau of Colombia, reproductive failure associated with abortions or birth of weak calves was the main clinical syndrome.

Animals↗

PubMed2002

A Jurassic mammal from South America.

The Jurassic period is an important stage in early mammalian evolution, as it saw the first diversification of this group, leading to the stem lineages of monotremes and modern therian mammals. However, the fossil record of Jurassic mammals is extremely poor, particularly in the southern continents. Jurassic mammals from Gondwanaland are so far only known from Tanzania and Madagascar, and from trackway evidence from Argentina. Here we report a Jurassic mammal represented by a dentary, which is the first, to our knowledge, from South America. The tiny fossil from the Middle to Late Jurassic of Patagonia is a representative of the recently termed Australosphenida, a group of mammals from Gondwanaland that evolved tribosphenic molars convergently to the Northern Hemisphere Tribosphenida, and probably gave rise to the monotremes. Together with other mammalian evidence from the Southern Hemisphere, the discovery of this new mammal indicates that the Australosphenida had diversified and were widespread in Gondwanaland well before the end of the Jurassic, and that mammalian faunas from the Southern Hemisphere already showed a marked distinction from their northern counterparts by the Middle to Late Jurassic.

Animals↗

PubMedDate not supplied

Helminthic control on grazing ruminants and environmental risks in South America.

The control of ruminant gastrointestinal nematodes and ectoparasites, one of the major production health problems, are heavily reliant on the systematic and sometimes abusive use of anthelmintic drugs. Endectocides are the most frequently used drugs, having high potency against arthropods and nematodes. Their dung pat residues enhance the risk of adverse effects on non-target invertebrates and on the general grazing cattle ecosystem. In this scenario, our objective is to review current knowledge of the agro-environmental and biodiversity impact and risks of endectocides in South America. The effects of faecal drug residues of ivermectin and doramectin on dung colonising invertebrates and dung degradation have been reported in studies carried out in the temperate centre of Argentina and in the subtropical region of Brazil. The results from Argentina showed a depression in invertebrate colonisation and degradation of dung recovered from endectocide treated cattle during the autumn. Comparisons have shown that ivermectin and doramectin have similar adverse effects. A decrease of Coleoptera larvae, Diptera larvae, Staphylinidae, Collembola, Acari and dung specific nematodes was noted in pats from both endectocides. The results from Brazil showed that dipterous larvae, Polyphaga coleopteran larvae and adults and mites were significantly reduced in the ivermectin treated group. The disturbances that macrocyclic lactones can produce on non-targeted invertebrates and on their associated participation in dung degradation and soil element recycling, are unpredictable and can negatively influence biodiversity and the agricultural ecosystem sustainability.

Animal Husbandry↗

PubMed1994

Basic, quantitative and experimental research phases of future ethnobotany with reference to the medicinal plants of South America.

Ethnobotany of the future will encompass what we perceive as three interrelated research phases. Basic ethnobotany includes the compilation and organization of information about biota obtained from indigenous and other peoples, such as obtaining data about useful plants and animals, understanding how peoples manage their environments and learning about their lexicons and classifications. This is what we try to do in the best possible way, directly in the field from original sources. These results can then be organized in many ways once species determinations are completed. They may also be organized using other types of information, the most obvious being chemical, medical and linguistic. Quantitative ethnobotany develops methods to allow quantitative description and to evaluate and analyse primary data sets. Original field research must be sufficiently structured and consistent, for example in relation to forest habitat and composition or to oral exchanges between informant and listener, so that statistical techniques may be used to test proposed hypotheses rigorously. This aspect of ethnobotany is in its infancy, yet it can be broadly utilized to comprehend more meaningfully and usefully ethnobotanically valued plants, particularly in the exceedingly diversified environments of tropical regions where because of community isolation practitioners are still most knowledgeable. Experimental ethnobotany involves the use of biota in search of products for industrial, medical and other purposes. Plant ethnomedicinal findings may set the stage for targeting materials which can be meaningfully analysed for chemical activity using appropriate biodirected assays. This approach in search of new pharmaceuticals is woefully underutilized today to the detriment of human health and a number of new strategies should be considered for future advancements in drug discovery. These aspects of ethnobotany will be evaluated largely in relation to current and future research in South America.

Forecasting↗

PubMed1998

Introduction to the post-Human Genome Project era, a target for interactions between polygenic and/or multiphenotypical components in cancer control in South America.

Epidemiological studies have suggested that the propensity to develop malignancy involves a complex mix of genetic and environmental determinants, however both older and innovative techniques display unresolved fundamental questions regarding etiology. Current barriers to achieving the potential benefit from this understanding are: 1) incomplete background on the various environmental and genetic factors involved in the carcinogenesis mechanism; 2) difficulties in accurately differentiating specific molecular subtypes and measuring the effective cellular exposure dose; and 3) difficulties in determining the multifactorial interaction between genetic and environmental factors. To extrapolate Human Genome Project research findings to the Post-Human Genome Project era, South America provides a large population and large-pedigree families, thus including genetically heterogeneous and less heterogeneous groups. An initial strategy might be to trace high risk populations and the respective exposures to which they are susceptible, such as: 1) migration, identifying rural migrant populations; 2) inherent susceptibility, studying "long term homogeneous populations" or large families living in similar rural environments; and 3) dissection of gene-environmental interaction

Environmental Exposure↗

PubMed1988

Alkaline phosphatase-conjugated oligonucleotide probes for enterotoxigenic Escherichia coli in travelers to South America and West Africa.

Several studies have demonstrated the usefulness of 32P-labeled recombinant DNA probes for identifying enterotoxigenic Escherichia coli (ETEC). The use of radioisotopes and X-ray development, however, severely handicaps the utility of DNA probes in most clinical laboratories. In this study, enzyme-labeled oligonucleotide probes for ETEC LT (heat-labile toxin) and ST (heat-stable toxin) genes were compared with the standard Y1 adrenal cell and suckling mouse assays for their ability to identify ETEC in a population of American adults experiencing acute episodes of diarrhea in South America and West Africa. The LT probe hybridized with 12% (64 of 529) of the E. coli colonies tested, whereas 11% (57 of 529) were positive by Y1 adrenal cell assay. DNA from 9% (47 of 529) of the E. coli colonies tested hybridized with the ST probe, whereas only 5% (28 of 529) produced ST as measured by the suckling mouse bioassay. For the patient samples tested, correlation between probe and bioassay for LT was 97%, or three discrepancies in 111 patients tested. Overall concordance of the ST probe and bioassay was 95%, or five discrepancies in 111 patients. Enzyme-labeled oligonucleotide probes represent a major advance in the diagnosis of ETEC-associated diarrheal disease and may be used in laboratories with minimal equipment.

Adult↗

PubMed2003

Vaccines and companion diagnostic tests for foot-and-mouth disease virus. An overview of the experience in South America.

Vaccination constitutes an important control policy for foot-and-mouth disease (FMD) in affected areas with advanced eradication programmes, as well as in free regions that decide to use immunization as a control measure after a recent introduction of the disease. However, considering that vaccinated animals exposed to FMD virus can establish sub-clinical infection and eventually remain persistently infected, availability of tools to identify sub-clinical infection and its silent transmission within and between herds, regardless of their vaccination state, is of utmost importance. In response to the need for new diagnostic tools to support the eradication campaigns implemented in 1988 in South America, during the past decade we have developed, validated and applied a highly sensitive and specific immuno-enzymatic system for recognition of persistence at a herd level. The system is based on the detection of antibodies against non-capsid proteins required for viral replication. These proteins, in principle, are removed from the viral suspensions destined for production of BEI inactivated vaccines. Within the validation steps, evaluation of potential induction of antibodies to non-capsid proteins caused by traces of these proteins eventually remaining in the vaccines was a major concern. This report presents a review on the experience gathered through the application of the system to various experimental and field immunization conditions. It was concluded that vaccination is not expected to induce antibody responses to non-capsid proteins that could lead to misinterpretation of serological investigations. Progress on the development of approaches towards vaccine certification to guarantee absence of interference will be discussed.

Animals↗

PubMed1986

A comparative study of Trypanosoma cruzi enzyme polymorphism in South America.

1. The electrophoretic patterns of 13 loci were used to compare the three main T. cruzi zymodemes (Z) circulating in North/Northeastern Brazil (Br 1 through 3) with the four principal zymodemes present in Southeastern (BrA through D) Brazil. 2. Nei's standard genetic distances (D) obtained by paired comparison of the Brazilian zymodemes indicate the presence of four divergent groups, separated by D = 1.18. Zymodemes BrB and BrD presented heterozygous patterns for six and three loci, respectively, for alleles coding for isoenzymes of the BrA/Br 2 and BrC zymodemes. 3. The 7 principal Brazilian zymodemes were in turn compared with the 11 other zymodemes thus far identified in South America (Colombia, Bolivia, Paraguay and Chile). Numerical taxonomy demonstrated the presence of three main infraspecific categories ('groups') separated by D greater than 1.08. Each of these 'groups' could be divided into 2 or 3 subgroups at D greater than or equal to 0.50. 4. The wide range of zymodemes within a group separated by a genetic distance ranging from 0 to 0.95, the presence of zymodemes with variable numbers of heterozygous patterns (1 to 6), the detection of two homozygous zymodemes circulating sympatrically with their corresponding heterozygous zymodemes, and the circumstantial evidence that the majority of zymodemes carrying heterozygous profiles are found in the domestic sector of subtropical regions and always associated with Triatoma infestans, indicates that genetic recombination can also occur presently under certain conditions.

Animals↗

PubMed1985

Epidemiology of neural tube defects in South America.

We present data from the Latin American Collaborative Study of Congenital Malformations (ECLAMC) on prevalence rates and etiologic factor associations in neural tube defects. Two series of data are analyzed: the A series, including 740,139 consecutive infants born in the 1967-1979 period suitable for secular trend analysis and case-control study of risk factors; and the B series, including 255,834 consecutive stillborn and liveborn infants of the 1980-1982 period suitable for prevalence rate analysis. Anencephaly was registered in 6.0/10,000 births, A spina bifida aperta in 6.2/10,000 births, and cephalocele in 2.4/10,000 births. A stable secular trend was observed for the frequency of all three neural tube defect types. Spina bifida was more frequent in Chile than in the rest of South America. No differences in prevalence rates were seen between tropical and non tropical areas. Parental consanguinity and environmental prenatal factors including maternal illnesses, drug intake, and radiation exposure were found in association with anencephaly and spina bifida.

Anencephaly↗

PubMed1985

Kondous laventicus, a new ceboid primate from the Miocene of the La Venta, Colombia, South America.

A new genus and species of fossil primate, Kondous laventicus, part of the Miocene La Venta primate fauna of Colombia, South America, is described here for the first time. Screening at a new quarry within the Monkey Unit of the Honda Formation, the Kyoto Site, has revealed dental remains of this new form of a large-sized ceboid. The La Ventan vertebrate fauna is comparable to the Friasian Land Mammal Age, indicating a middle Miocene age. Biostratigraphic studies suggest a 13.6-15.2 Ma for the Friasian faunal zone. Kondous is most closely allied to extant spider monkeys, Ateles, providing the first fossil evidence of their phylogeny. It also implies a nearly three-fold discrepancy between the molecular and paleontological estimates of the age of the Ateles lineage.

Animals↗

PubMed1999

Ozone depletion and UVB radiation: impact on plant DNA damage in southern South America.

The primary motivation behind the considerable effort in studying stratospheric ozone depletion is the potential for biological consequences of increased solar UVB (280-315 nm) radiation. Yet, direct links between ozone depletion and biological impacts have been established only for organisms of Antarctic waters under the influence of the ozone "hole;" no direct evidence exists that ozone-related variations in UVB affect ecosystems of temperate latitudes. Indeed, calculations based on laboratory studies with plants suggest that the biological impact of ozone depletion (measured by the formation of cyclobutane pyrimidine dimers in DNA) is likely to be less marked than previously thought, because UVA quanta (315-400 nm) may also cause significant damage, and UVA is unaffected by ozone depletion. Herein, we show that the temperate ecosystems of southern South America have been subjected to increasingly high levels of ozone depletion during the last decade. We found that in the spring of 1997, despite frequent cloud cover, the passages of the ozone hole over Tierra del Fuego (55 degrees S) caused concomitant increases in solar UV and that the enhanced ground-level UV led to significant increases in DNA damage in the native plant Gunnera magellanica. The fluctuations in solar UV explained a large proportion of the variation in DNA damage (up to 68%), particularly when the solar UV was weighted for biological effectiveness according to action spectra that assume a sharp decline in quantum efficiency with increasing wavelength from the UVB into the UVA regions of the spectrum.

Atmosphere↗

PubMed1995

HTLV-I from Iranian Mashhadi Jews in Israel is phylogenetically related to that of Japan, India, and South America rather than to that of Africa and Melanesia.

A new endemic focus of human T-lymphotropic virus type I (HTLV-I) was recently reported among Mashhadi Jews, a group of immigrants from northeastern Iran to Israel. We extracted DNAs from fresh peripheral blood mononuclear cells (PBMCs) and/or gargle mouthwash from 10 HTLV-I carriers, who consisted of members of one family, and HTLV-I-associated myelopathy (HAM) and adult T-cell leukemia (ATL) patients. Long terminal repeat (LTR) regions of proviral DNAs were sequenced and analyzed phylogenetically. In a phylogenetic tree, all the Mashhadi HTLV-I isolates belonged to subtype A, one of the three subtypes of the cosmopolitan type of HTLV-I, and made a tight cluster distinct from the other isolates of subtype A from Japan, India, the Caribbean Basin, and South America. Although a few nucleotide substitutions were observed among the clones sequenced, no characteristic sequence variation was found in different disease manifestations, even in one family or different sources of DNA preparation.

Adult↗

PubMed2006

Metaphase and array comparative genomic hybridization: unique copy number changes and gene amplification of medulloblastomas in South America.

Tumors of the central nervous system are the second most frequent malignancy of childhood, accounting for the majority of cancer-related deaths in this age group. Among these tumors, medulloblastomas (MB) remain in need of further genomic characterization toward understanding of pathogenesis and outcome predictors. Eight pediatric embryonal brain tumors were analyzed: five MB (one being desmoplastic), one PNET, one medulloepithelioma, and one ependymoblastoma. Analyses identified genomic imbalances, including the gain of 16p and the nonsyntenic coamplification of MYCN and TERT loci. More detailed FISH analysis showed that coamplification of MYCN and TERT in one of the MBs manifested as dispersed nuclear speckling, consistent with the presence of double minute chromosomes. There was considerable cell-to-cell copy number heterogeneity present, but it was clear that both genes were amplified concordantly. The amplification of oncogenes seems to play an important role in the pathogenesis of MB, and the association between MYCN and TERT amplifications and poor prognosis has not been well recognized. The uncharacteristic pattern of genomic imbalances detected in MB tumors may be a reflection of the characteristics of these tumors occurring in South America.

Adolescent↗

PubMed2006

Cactophilic Drosophila in South America: a model for evolutionary studies.

The Drosophila buzzatii cluster is composed of seven cactophilic species and their known geographical distribution encompasses the open vegetation diagonal, which includes the morphoclimatic Domains of the Caatinga, Chaco and Cerrado, which are situated between the Amazon and the Atlantic forests. Besides these areas, these cactophilic species are also found in a narrow strip along the Atlantic coast from northeastern Brazil to the southern tip of the country. The hypothesis of vicariant events, defining the core areas of each species, is proposed to explain the historical diversification for the cluster. The intraspecific analysis for the cluster shows a population structure with gene flow restricted by distance, range expansion with secondary contact resulting in introgression and simpatry, especially in the limits of the species distribution, polytypic populations and assortative mating in inter population experiments. There is a variation related to these events that depends on the species and geographic origin of the population analyzed. These events are, hypothetically, described as the results of expansion and retraction of the population ranges, as a consequence of their association with cacti, which theoretically follow the expansion and retraction of dry areas during the paleoclimatic oscillations in South America, as that promoted by the glacial cycles of the Quaternary. The Drosophila buzzatii cluster is divided into two groups. The first one is composed of D. buzzatii, a species that has a broad geographic distribution and no significant differentiation between its populations. The second is the Drosophila serido sibling set, which encompasses the others species and is characterized by a significant potential for differentiation.

Animals↗

PubMed1999

Attaining health for all through community partnerships: principles of the census-based, impact-oriented (CBIO) approach to primary health care developed in Bolivia, South America.

This article describes a flexible primary health care methodology which was developed by Andean Rural Health Care and its colleagues in Bolivia, South America. This methodology, the census-based, impact-oriented (CBIO) approach to primary health care, involves determining local health priorities as defined both by locally acquired epidemiologic information and by the local people themselves. The CBIO approach to primary health care is now functioning successfully at seven program sites in Bolivia, which together serve 75,000 people in urban and rural communities in three distinct cultural and ecological regions of the country. High levels of coverage of basic health services can be achieved through a system of 'epidemographic' surveillance of all families and through home delivery, when needed, of priority services to those at risk. When the services provided are based on local health priorities, when they are provided in a technically effective manner, and when the community has a strong partnership in planning, implementation and evaluation, then the CBIO approach to primary health care will lead to measurable health improvements as defined by changes in population-based rates of mortality and illness in the community. On the basis of our experience, we believe that the CBIO approach offers great potential for strengthening the effectiveness of local health programs in impoverished communities around the world in a way which fosters community ownership and, hence, long-term sustainability.

Bolivia↗

PubMed1983

Endomyocardial disease in South America--report on 23 cases in Venezuela.

Twenty-three cases of endomyocardial disease (ED) are presented, studied in Venezuela, a tropical country in northern South America. The diagnosis was confirmed in 18 cases by means of pathological studies, and in 5 cases by angiocardiography which showed the characteristic obliterative ventricular lesions. Eosinophilia was present in 35% of the patients. The most frequent clinical feature was heart failure associated with mitral regurgitation. Systemic embolism was the first clinical feature in 5 cases. In 2 cases, ED was associated with autoimmune haemolytic anaemia or vasculitis. Necropsy revealed a predominance of the left-sided (9/16 cases) and biventricular (6/16 cases) types. The pathological lesions were characterised by fibrous thickening of the endocardium at the apex and the ventricular inflow tracts extending to the myocardium and involving the atrioventricular valves. ED is frequently misdiagnosed as rheumatic valvular cardiopathy. The two-dimensional echocardiogram is a very useful procedure for determining the spatial anatomy of ED. The echo findings were closely correlated with ventriculographic and necropsy findings. Even though ED is widely spread around the world, it is most frequently found in tropical and subtropical countries in Africa, Asia and America, such as Venezuela and Brazil. This suggests that there are aetiological factors in these latitudes, about which little is known.

Adolescent↗

PubMed1978

Body size and form of children of predominantly black ancestry living in West and Central Africa, North and South America, and the West Indies.

Stature, sitting height, hip width, arm and calf circumferences and body weight have been measured in black children of Richland County, South Carolina. Lower limb height and three indices of body shape were obtained from the measurements. Sample size exceeded 200 for each of five age-sex groups representing girls and boys aged 6 years, girls and boys aged 9 years, and boys aged 11 years. Comparisons are made with findings from previous research on children of predominantly black ancestry living in west and central Africa, the West Indies, and North, Central and South America. Black children of Richland County measured during 1974--77 are taller than black children studied since 1960 in Angola, Chad, Ghana, Liberia, Nigeria, Senegal, Uganda, Anguilla, Barbados, Cuba, Guyana, Jamaica, Nevis, St. Kitts, St. Vincent, and Surinam. Children of well-to-do black families in Accra and Ibadan are no taller or heavier than black children of Richland County taken without regard to socio-economic status. In hip width, averages for Richland County black children are larger than those for children of the Hutu and Yoruba tribes; in arm girth they are larger than children of the Hutu and Tutsi tribes. Age changes and group differences are reported for hip width relative to lower limb height, and lower limb height relative to sitting height. During childhood, the hip/lower limb index decreases, and the lower limb/sitting height index increases. Almost identical hip/lower limb indices characterize black populations in Africa, Cuba, and the United States.

Africa↗