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PubMed2004

Decision tree algorithm for detection of spatial processes in landscape transformation.

The conversion of landscapes by human activities results in widespread changes in landscape spatial structure. Regardless of the type of land conversion, there appears to be a limited number of common spatial configurations that result from such land transformation processes. Some of these configurations are considered optimal or more desirable than others. Based on pattern geometry, we define ten processes responsible for pattern change: aggregation, attrition, creation, deformation, dissection, enlargement, fragmentation, perforation, shift, and shrinkage. A novelty in this contribution is the inclusion of transformation processes causing expansion of the land cover of interest. Consequently, we propose a decision tree algorithm that enables detection of these processes, based on three parameters that have to be determined before and after the transformation of the landscape: area, perimeter length, and number of patches of the focal landscape class. As an example, the decision tree algorithm is applied to determine the transformation processes of three divergent land cover change scenarios: deciduous woodland degradation in Cadiz Township (Wisconsin, USA) 1831-1950, canopy gap formation in a terra firme rain forest at the Tiputini Biodiversity Station (Amazonian Ecuador) 1997-1998, and forest regrowth in Petersham Township (Massachusetts, USA) 1830-1985. The examples signal the importance of the temporal resolution of the data, since long-term pattern conversions can be subdivided in stadia in which particular pattern components are altered by specific transformation processes.

Algorithms↗
PubMed1996

DNA polymorphism among Fusarium oxysporum f.sp. elaeidis populations from oil palm, using a repeated and dispersed sequence "Palm".

A worldwide collection, of 76 F. oxysporum f.sp. elaeidis isolates (Foe), and of 21 F. oxysporum isolates from the soil of several palm grove was analysed by RFLP. As a probe, we used a random DNA fragment (probe 46) from a genomic library of a Foe isolate. This probe contains two different types of sequence, one being repeated and dispersed in the genome "Palm", the other being a single-copy sequence. All F. oxysporum isolates from the palm-grove soils were non-pathogenic to oil palm. They all had a simple restriction pattern with one band homologous to the single-copy sequence of probe 46. All Foe isolates were pathogenic to oil palm and they all had complex patterns due to hybridization with "Palm". This repetitive sequence reveals that Foe isolates are distinct from the other F. oxysporum palm-grove soils isolates. The sequence can reliably discriminate pathogenic from non-pathogenic oil palm isolates. Based on DNA fingerprint similarities, Foe populations were divided into ten groups consisting of isolates with the same geographic origin. Isolates from Brazil and Ecuador were an exception to that rule as they had the same restriction pattern as a few isolates from the Ivory Coast, suggesting they may originated from Africa.

Fusarium↗
PubMed2005

Artificial cranial deformation in newborns in the pre-Columbian Andes.

INTRODUCTION: Artificial deformation of the neonatal cranial vault is one form of permanent alteration of the body that has been performed by the human being from the beginning of history as a way of differentiating from others. These procedures have been observed on all continents, although it became widespread practice among the aborigines who lived in the Andean region of South America. It has been suggested that the expansion of this practice started with the Scythians from their original settlements in central Asia and spread toward the rest of Asia and Europe, and it is believed that Asiatic people carried this cultural custom to America when they arrived on the current coasts of Alaska after crossing the Strait of Behring. The practice of deforming newborn heads was present in the whole of the American continent, from North America to Patagonia, but cranial molding in neonates was most widely practiced in the Andean region, from Venezuela to Guyana, Colombia, Ecuador, Peru, Bolivia, Chile, and Argentina. METHODS: Intentional deformation of the head in neonates was carried out in different ways: by compression of the head with boards and pads; by compression with adjusted bindings; or by restraining the child on specially designed cradle-boards. PURPOSE: The purpose of head shaping varied according to culture and region: while in certain regions it was a symbol of nobility or separated the different social groups within society, in others it served to emphasize ethnic differences or was performed for aesthetic, magical or religious reasons. CONCLUSION: There is no evidence of any neurological impairment among indigenous groups who practiced cranial deformations in newborns.

Adult↗
PubMed2006

Genetic variability of Tunga penetrans (Siphonaptera, Tungidae) sand fleas across South America and Africa.

Tunga penetrans is a widely distributed sand flea, infecting men and domestic animals. It originated in South America, but it is now also endemic of Sub-Saharan Africa due to a recent accidental introduction. Previous genetic analyses indicated a very limited variability in the Ecuadorian populations; on the other hand, samples from Madagascar resulted to be genetically isolated. To better examine the genetic variability of T. penetrans, a wider sampling was analysed for mitochondrial (cytochrome oxidase II) and nuclear (ribosomal internal transcribed spacer [ITS] 2) DNA sequences. The mitochondrial marker confirms the low genetic variability, with few haplotypes characterizing the majority of individuals from different populations. Haplotype distribution is in agreement with a recent colonization of Africa and with a rapid spreading across this continent. Moreover, a consistent gene flow between the Pacific and Atlantic South American populations emerges, possibly due to human and/or animal cross-Andean dispersal. On the other hand, the ITS2 marker depicts a sharply diverging pattern with samples collected in Ecuador unequivocally distinguished from the Brazilian and African ones. On the whole, taking into account also the molecular features of the marker used, data here presented are better interpreted in the light of a high dispersal ability of T. penetrans, probably reducing the phylogeographic signal.

Africa↗
PubMed2005

Nutritional differences and leaf acclimation of climbing plants and the associated vegetation in different types of an Andean montane rainforest.

Climbing plants are known to play an important role in tropical forest systems, but key features for their distribution are only partly understood. Investigation was carried out to find if climbers differ from self-supporting vegetation in their adjustment of leaf parameters over a wide variety of light regimes in different forest types along an altitudinal gradient. Relative photon flux density (PFDrel) was assessed above 75 pairs of strictly linked climbers and supporting vegetation on seven plots between 2,020 and 2,700 m a.s.l. along a mountain range in South-Ecuador up to the Páramo vegetation. Leaf samples from both growth forms were analyzed for leaf area (LA), specific leaf mass (LMA), mass and area-based carbon and nitrogen concentration (C, Carea, N, and Narea) and concentrations of P, K, Ca, Mg, Mn and Al. Leaf size of climbers was independent of general light condition, whereas the leaf size of the self-supporting vegetation increased in shade. LMA increased as expected with altitude and irradiance for both growth forms, but climbers generally built smaller leaves with lower LMA. N, P, and K concentrations were higher in the leaves of climbers than in their supporters. Relationships of LMA and Narea to the light conditions were more pronounced within the climbers than within their supporters. Slope for the regression between climber's Narea and LMA was twice as steep as for the supporter leaves. Al accumulators were only found within the self-supporting vegetation. The investigated traits indicate improved adjustment towards light supply within climbers compared to self-supporting vegetation. Thus climbing plants seem to have a higher potential trade off in resource-use efficiency regarding irradiance and nutrients.

Peru↗
PubMed2006

Enantioselective Baeyer-Villiger oxidation of bicyclo[3.2.0]hept-2-en-6-One with fungi: optimization of biotransformation and use of TiO2 as support of cell growth.

Fungi from Amazonian forest soil (Ecuador) and an Italian factory were screened for Baeyer-Villiger (BV) oxidation of bicyclo [3.2.0]hept-2-en-6-one to 2-oxabicyclo[3.3.0]oct-6-en-3-one (Corey's lactone). Isolates of Fusarium sp. and F. solani produced the (+)-(1R,5S)-lactone while isolates of Aspergillus terricola and A. amazonicus afforded the (-)-(1S,5R)-lactone. Highest conversions (85% yield and 70% enantiomeric excess) were obtained with A. amazonicus grown in presence of 2.7 mM titanium dioxide.

Aspergillus↗
PubMed2006

Critical sampling points methodology: case studies of geographically diverse watersheds.

Only with a properly designed water quality monitoring network can data be collected that can lead to accurate information extraction. One of the main components of water quality monitoring network design is the allocation of sampling locations. For this purpose, a design methodology, called critical sampling points (CSP), has been developed for the determination of the critical sampling locations in small, rural watersheds with regard to total phosphorus (TP) load pollution. It considers hydrologic, topographic, soil, vegetative, and land use factors. The objective of the monitoring network design in this methodology is to identify the stream locations which receive the greatest TP loads from the upstream portions of a watershed. The CSP methodology has been translated into a model, called water quality monitoring station analysis (WQMSA), which integrates a geographic information system (GIS) for the handling of the spatial aspect of the data, a hydrologic/water quality simulation model for TP load estimation, and fuzzy logic for improved input data representation. In addition, the methodology was purposely designed to be useful in diverse rural watersheds, independent of geographic location. Three watershed case studies in Pennsylvania, Amazonian Ecuador, and central Chile were examined. Each case study offered a different degree of data availability. It was demonstrated that the developed methodology could be successfully used in all three case studies. The case studies suggest that the CSP methodology, in form of the WQMSA model, has potential in applications world-wide.

Ecosystem↗
PubMed1994

Determination and in-depth chromatographic analyses of alkaloids in South American and greenhouse-cultivated coca leaves.

Methodology is described for the detection and/or determination of cocaine and minor alkaloids in South American coca as well as in greenhouse- and tropical-cultivated field coca of known taxonomy. Coca leaf from Bolivia, Peru, Ecuador and Colombia were subjected to the determination of cocaine, cis- and trans-cinnamoylcocaine, tropacocaine, hygrine, cuscohygrine and the isomeric truxillines. The greenhouse samples were cocaine-bearing leaves of the genus Erythroxylum and included E. coca var. coca, E. novogranatense var. novogranatense and E. novogranatense var. truxillense, and the alkaloids determined were cocaine, ecgonine methyl ester, cuscohygrine, tropacocaine and the cinnamoylcocaines. The tropical-cultivated coca were E. novogranatense var. novogranatense and E. coca var. coca. Cocaine and minor alkaloids were isolated from basified powdered leaf samples using a toluene extractant, followed by acid-Celite column chromatography. The isolated alkaloids were determined by capillary gas chromatography with flame ionization or electron-capture detection. Methodology is also presented for the isolation and mass spectral analysis of numerous trace-level coca alkaloids of unknown structure.

Alkaloids↗
PubMed1991

DNA restriction polymorphism in wild isolates of Spodoptera frugiperda nuclear polyhedrosis virus.

Restriction endonuclease analysis was used to examine variation in DNA of 22 wild isolates of Spodoptera frugiperda nuclear polyhedrosis virus (SfNPV). Eleven of the 15 isolated from Louisiana were distinguishable based on restriction fragment profiles from the enzymes BamHI, HindIII, and EcoRI. There was significant genetic variation in SfNPV isolates within single agricultural fields. Nucleotide sequence divergence values, based on restriction fragment profiles, indicated that genetic variation among isolates foreign to Louisiana (Ohio, Ecuador, Mexico, Georgia, Colombia, and Venezuela) was greater than that among the Louisiana isolates. However, certain foreign isolates were similar to or identical with Louisiana isolates. Genetic variation of the viral DNA was not influenced by the insect's host plan species.

Animals↗
PubMed1993

Imperforate anus, delayed presentation in a 7-year-old girl.

Most of the cases of imperforate anus should be discovered at birth, during the initial physical examination. This case represents the status of Third World rural perinatal care, wherein delivery of an infant by a midwife in poverty stricken area of mountainous Jipijapa, Ecuador, failed to reveal the anomaly during the cursory examination. Moreover, the cultural taboos of the Jipijapan agricultural community further delayed the diagnosis. A 7-year-old girl with imperforate anus presenting with a rectovaginal fistula is reported. Specific findings in the case, therapy, and an approach to the diagnosis are discussed.

Anus, Imperforate↗
PubMed1984

Serum antibody levels in human paragonimiasis before and after therapy with praziquantel.

Enzyme immunoassays (ELISA) and indirect haemagglutination (IHA) were used to determine IgG and IgE serum antibody levels in 43 patients from Ecuador before and after therapy with praziquantel. ELISA indicated infection more sensitively than IHA. The tendency of increasing antibody levels between the first and second month after therapy was more distinct when measured by IHA, whereas the decreases of antibody levels between the third and sixth month after treatment was more distinct when measured by ELISA. The IgG ELISA for detecting long persisting antibody was more sensitive than IHA.

Antibodies↗
PubMedDate not supplied

Snake venoms in science and clinical medicine. 2. Applied immunology in snake venom research.

Enzyme-linked immunosorbent assay (ELISA) is a very important tool for studying both the epidemiology and clinical effects of snake bite in man. For epidemiology ELISA depends on the development and persistence of specific humoral venom antibody in previous snake bite victims. In the Nigerian savanna 63% of previous bite victims possessed specific venom antibodies against Echis carinatus venom; in Ecuador, where there is a 5% annual mortality due to snake bite in a population of Waorani Indians, venom antibodies against a wide range of different venoms were identified in previous bite victims using ELISA. In certain areas it is often not possible, using the symptoms of envenoming, to determine which species of snake has bitten the patient. Field studies using ELISA in Nigeria and Thailand have been successful in establishing the species responsible for envenoming. Current studies are in progress on the development of a rapid immunoassay which should be capable of detecting the biting species within 5-10 min of sampling from the admission patient. This will be useful for the clinician as it will enable the rapid detection of the species responsible for envenoming and, therefore, the use of the correct antivenom. Experimental work on the development of new methods of antivenom production includes immunization of experimental animals with venom/liposome preparations, the preparation of venom antigens using monoclonal antibodies on affinity columns, and recombinant deoxyribonucleic acid technology. Liposomal immunization requires only a single injection of venom to obtain a rapid, high level and protective immune response. Venom liposomes may also be given orally resulting in a serum immunoglobulin G immune response in experimental animals. Use of such a system may eventually result in immunization of man in areas of high snake bite incidence and mortality.

Animals↗
PubMed1989

The quality control of tuberculin PPD products from seven Latin American laboratories.

The Pan American Health Organization, through its Pan American Zoonoses Center (CEPANZO), distributes the concentrated stock solution of PPD batch RT23 (1 mg ml-1 = 50,000 TU ml-1) to national central laboratories. In the laboratories the stock solution is diluted to 2 TU/0.1 ml and dispensed with the addition of Tween 80 and either chinosol or phenol as preservatives in rubber-stoppered vials for use in the Mantoux test. The expiry date is usually fixed at six months after filling. Samples of nine lots of PPD 2 TU from seven countries (Argentina, Brazil, Colombia, Dominican Republic, Ecuador, Paraguay and Uruguay) were received by CEPANZO for quality control. The biological activity and phenol concentrations of these samples were assayed periodically after storage at 4, 25 or 37 degrees C either unopened or opened and re-used in a manner simulating extreme field conditions of use and storage. The object of the study was to determine the stability of the biological activity as well as the maintenance of sterility of these conditions with a view to assessing the need for stricter requirements for the labelling of tuberculin. The results obtained showed that PPD 2 TU with 0.4-0.5% (w/v) phenol added, and dispensed in vials, was stable in its biological activity and maintained its sterility. Therefore, it seems unnecessary to issue stricter requirements than those currently applied.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Biotechnology in the Andean Group: common policies and instruments.

Although applications of biotechnology have taken a slower pace than initially anticipated, they certainly hold potentials for contributing to the social welfare and economic growth of all nations. Aware of such potentials, the andean countries (Bolivia, Columbia, Ecuador, Peru and Venezuela) individually and collectively, within their economic integration process, are making efforts to develop this new technology area. At the national level, science and technology policies and strategies are being revamped to create an appropriate environment for the development and application of biotechnology and several projects are under execution. These efforts still need, however, further political support and investment. In 1969 the andean countries established an economic integration agreement (the Cartagena Agreement), which included technology as one of its main concerns. For 22 years conceptual and operational developments have taken place creating joint capabilities in many technology areas, including biotechnology. In the last two years the pace has slowed down and is not accompanying national efforts. This is particularly serious as no country can by itself fully develop biotechnology. In spite of current difficulties the Andean Group is well placed to accelerate the development of biotechnology through the application of existing policies and legislation at communitarian level.

Biotechnology↗
PubMed1991

The epidemiology and economic impact of llama parasites.

Camelids are distributed over vast areas of South America, ranging from south Ecuador to north Chile, with high concentrations in Peru and Bolivia. Guillermo Leguio discusses the effects that parasitic infections have on the health and productivity of these animals.

Journal Article↗
PubMed1987

Field-adapted method for high-performance thin-layer chromatographic detection and estimation of chloroquine and desethylchloroquine in urine.

A high-performance thin-layer chromatographic (HPTLC) method which can be used in remote field locations lacking electricity has been developed for selective and sensitive detection and estimation of chloroquine (Cq), desethylchloroquine (DECq) and two other antimalarial compounds in urine. The method requires a single extraction step and has a detection limit of 0.25 micrograms/ml for both Cq and DECq. The HPTLC method was coupled with a colorimetric field assay for Cq and metabolites in urine and a field-interfaced, laboratory-based, high-performance liquid chromatographic assay of Cq and DECq in finger-stick blood to survey antimalarial drug use practices in Esmeraldas Province in northwestern Ecuador. Fourteen of 66 patients from whom urine samples were obtained were found to have detectable Cq and DECq. Results of the three assays are compared for these individuals, and the role of the HPTLC method in field studies is assessed.

Child, Preschool↗
PubMed1982

Chuchuhuasha - a drug used in folk medicine in the Amazonian and Andean areas. A chemical study of Maytenus laevis.

In the high Amazonian basin a plant named chuchuasha, (or chuchuaso) is used in traditional medicine for several purposes in the form of an alcoholic extract. This plant, a Maytenus species, most probably Maytenus laevis, grows in the subandean region of the Amazonian basin (Peru, Ecuador, Colombia). Antitumor and anti-inflammatory properties were recently attributed to the extracts of the root bark of the plant. The composition of the extract of M. laevis from the Putumayo area of Colombia was studied in order to establish the active principle responsible for these activities. The presence of phenoldienones (tingenone, 22-hydroxytingenone), a catechin (4'-methyl-(-)-epigallocatechin) and proanthocyanidins (Ouratea-proanthocyanidins A and B) was established. The biological activities of these compounds confirm the properties of the extracts of the plant claimed by traditional medicine.

Antineoplastic Agents, Phytogenic↗
PubMed1992

The Moraceae-based dart poisons of South America. Cardiac glycosides of Maquira and Naucleopsis species.

The use of cardenolide-containing Moraceae in the dart poisons of South America is reviewed. Those prepared by the Chocó Indians of western Colombia--called niaará or kieratchi--have probably been made from the latex of Naucleopsis amara and N. glabra. In Ecuador, the Colorado Indians used N. chiguila, while the Coaiquer Indians still derive a poison from the latex of N. naga and the Cayapá Indians occasionally make use of a blowgun poison, hambi, which probably also comes from a Naucleopsis species. The Kaborí (Rio Uneiuxi Makú) Indians of north-western Brazil may have utilized Maquira coriacea, but a more recent collection documents N. mello-barretoi latex as a source of their poison. The Tikuna Indians of western Brazil included leaves and bark of N. stipularis in one of their poisons. The principal cardiac glycosides present in Maquira species are strophanthidin-based and the main ones occurring in Naucleopsis species are antiarigenin- as well as strophanthidin-based. The structures of two new glycosides, isolated from dart-poison samples, have been established as strophanthidin beta-D-glucomethylosido-D-alloside and beta-D-digitoxosido-D-alloside. The former is a major component of pakurin, the crystalline glycoside mixture prepared by Santesson in 1928 from a Chocó Indian poison.

Animals↗