[Young woman with long-course back pain].
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Back Pain↗
Biomedical subjects
E Llop
Publications and source records attributed to E Llop.
Recombinant erythropoietin and analogues: a challenge for doping control.
Erythropoietin (EPO) increases the number of circulating erythrocytes and thus muscle oxygenation. The availability of the recombinant protein (rEPO) has increased the risk of its illegal use in sports, its detection being a difficult challenge. Five different hematopoietic parameters were initially chosen as indirect markers of rEPO abuse: concentration of serum EPO, concentration of serum-soluble transferrin receptors (sTFr), hematocrit, percentage of reticulocytes, and percentage of macrocytes. New models considering only hemoglobin, serum EPO concentration, and percentage of reticulocytes are simpler and seem to be more sensitive when low doses of rEPO are used. A more direct method of urine analysis (isoelectrofocusing, double blotting, and chemiluminescent detection) based on the charge differences between rEPO and endogenous EPO, related to their carbohydrate composition, provides proof of rEPO use. Furthermore, this approach permits the detection of darbepoetin, a direct analogue of EPO also known as NESP ("new erythropoiesis stimulating protein"). Recently a protein conjugate, "synthetic erythropoiesis protein" (SEP), containing precision-length, monodisperse, negatively charged polymers instead of oligosaccharides has been synthesized. Finally, EPO-mimetics are molecules capable of acting as EPO in dimerizing the EPO receptor. Two kinds of EPO-mimetics have been described: peptides and nonpeptides. The enhancement of oxygen availability to muscles by rEPO, analogues, and mimetics constitutes one of the main challenges to doping control. Major steps have already been developed for detection ofrEPO and some analogues. In the near future, the transfection to an athlete's body of genes that code for erythropoietin might be an emerging doping issue, and sports authorities have incorporated "gene doping" among the prohibited practices.
Biomarkers↗
Genetic variants of serum butyrylcholinesterase in Chilean Mapuche Indians.
We estimated the frequencies of serum butyrylcholinesterase (BChE) alleles in three tribes of Mapuche Indians from southern Chile, using enzymatic methods, and we estimated the frequency of allele BCHE*K in one tribe using primer reduced restriction analysis (PCR-PIRA). The three tribes have different degrees of European admixture, which is reflected in the observed frequencies of the atypical allele BCHE*A: 1.11% in Huilliches, 0.89% in Cuncos, and 0% in Pehuenches. This result is evidence in favor of the hypothesis that BCHE*A is absent in native Amerindians. The frequencies of BCHE*F were higher than in most reported studies (3.89%, 5.78%, and 4.41%, respectively). These results are probably due to an overestimation of the frequency of allele BCHE*F, since none of the 20 BCHE UF individuals (by the enzymatic test) individuals analyzed showed either of the two DNA base substitutions associated with this allele. Although enzymatic methods rarely detect the presence of allele BCHE*K, PCR-PIRA found the allele in an appreciable frequency (5.76%), although lower than that found in other ethnic groups. Since observed frequencies of unusual alleles correspond to estimated percentages of European admixture, it is likely that none of these unusual alleles were present in Mapuche Indians before the arrival of Europeans.
Alleles↗
Genetic marker variation in coastal populations of Chile.
Gene frequencies for nine genetic marker systems are presented for the following Chilean coastal populations: Paposo, Carelmapu, Laitec and Ukika. Historical and anthropological data suggest the presence of descendants of the Amerindian populations, specifically of Changos, Cuncos, Chonos and Yamanas in these populations. Results indicate that the studied groups maintain an important aboriginal genetic composition. According to Amerindian admixture estimates, the genetic isolation of coastal populations is lower than that of inland populations, suggesting that proximity to the sea facilitated gene flow. Genetic distances and dendrograms were obtained for these populations and another four Chilean Indian populations. Results agree with expectations, taking geographic isolation and non-aboriginal admixture into account.
Chile↗
Origin and evolutionary relationships of native Andean populations.
This paper represents an effort to explore the origin and the evolutionary relationships of native Andean populations using a multidisciplinary approach. Archeological and linguistic evidence is briefly reviewed. A genetic distance analysis among major linguistic groupings and among Andean and Amazonian native populations, together with information obtained from archaeological and linguistic sources was used to generate a migration model. It is suggested that in the late Pleistocene a group of nomadic hunters entered South America through the Isthmus of Panama and split afterwards into two groups, one moving southward into the central and south Andean areas and after crossing the Colombian, Equador and Peruvian highlands to people northwestern Argentina, the open park country of east Brazil and the Argentine Pampas. The second group migrated eastwards into Venezuela and Guyana and later southward, peopling the Brazilian Amazon. Following available waterways the Amazonian Indians expanded east and west arriving probably at the eastern slopes of the Andes some 3,500 years ago. It is hypothesized that present day Andean natives are descendants of the Amazonian groups that migrated eastwards.
Acclimatization↗
Mitochondrial DNA polymorphisms in Chilean aboriginal populations: implications for the peopling of the southern cone of the continent.
The mitochondrial DNAs (mtDNAs) from individuals belonging to three Chilean tribes, the Mapuche, the Pehuenche, and the Yaghan, were studied both by RFLP analysis and D-loop (control region) sequencing. RFLP analysis showed that 3 individuals (1.3%) belonged to haplogroup A, 19 (8%) to haplogroup B, 102 (43%) to haplogroup C, and 113 (47.7%) to haplogroup D. Among the 73 individuals analyzed by D-loop sequencing, we observed 37 different haplotypes defined by 52 polymorphic sites. Joint analysis of data obtained by RFLP and sequencing methods demonstrated that, regardless of the method of analysis, the mtDNA haplotypes of these three contemporary South American aborigine groups clustered into four main haplogroups, in a way similar to those previously described for other Amerindians. These results further revealed the absence of haplogroup A in both the Mapuche and Yaghan as well as the absence of haplogroup B in the Yaghan. These results suggest that the people of Tierra del Fuego are related to tribes from south-central South America.
Base Sequence↗
[Genetic composition of Chilean population: rural communities of Elqui, Limari and Choapa valleys].
BACKGROUND: The population that inhabits the semiarid Northern zone of Chile arose from ethnic admixture between aborigines, Spanish conquerors and the influx, during the XVII century, of foreign aboriginal workers and a minority of African slaves. AIM: To study the phenotypic frequencies of 15 genetic markers among populations inhabiting valleys in the Northern zone of Chile and to estimate the percentage of indigenous, African and Caucasian admixture in these populations. MATERIAL AND METHODS: Throughout five different field works, blood samples were obtained from 120 individuals living in the Elqui valley, 120 individuals living in the Limari valley and 85 living in the Choapa valley. Blood groups, erythrocyte enzymes, plasma proteins and HLA markers were typified. RESULTS: In the populations studied, the contribution of non indigenous genes was low in relation with the time elapsed since the Spanish invasion. The Hardy-Weinberg disequilibrium for MNS system would have microevolutive implications. The admixture percentages in these valleys confirm ethnic and historic information. The variation of the enzyme esterase D is identical to that of other Chilean populations. CONCLUSIONS: The phenotypic and genetic frequencies in the three populations studied and different admixture of indigenous genes is inversely proportional to the geographic distance from Santiago, in Central Chile.
Blood Group Antigens↗
[Genetics of addictive disorders].
Given the spectacular advances of genetics during the last five years, it seems appropriate to revisit the important subject of genetics of alcoholism and substance abuse. In recent studies alcohol abuse was shown to have an hereditability of roughly 38%, whereas psychostimulant and opiate use exhibit hereditabilities of 11 to 45%. The hereditability of smoking was found to be around 50%. There is a strong comorbidity between alcoholism and smoking. More than 80% of alcoholics smoke cigarettes in the U.S.A. Other genetic methods such as linkage analysis, allele sharing methods, association studies and analysis of inbred, transgenic and gene-knockout rodents, have partially agreed in showing that the 5HT-1B serotonin receptor and the DRD1, DRD2 and DRD4 dopamine receptors, as well as the dopamine transporter DAT, play an important role in behaviors related to alcoholism and substance abuse. Some neurochemical markers, as for example monoamine oxidase and adenylate cyclase have also been implicated in addictive disorders. The aldehyde dehydrogenase allele ALDH2*2 has a protective effect against alcoholism. Two whole genome linkage studies have shown linkage to chromosomal regions that are in the proximity of the DRD4 dopamine receptor, the GABA receptor gene cluster and the alcohol dehydrogenase gene cluster.
Alcoholism↗
T-cell receptor variable alpha (TCRAV) polymorphisms in European, Chinese, South American, AfroCaribbean, and Gambian populations.
Interactions involving the T-cell receptor (TCR) and major histocompatibility complex (MHC) are fundamental to the generation of a specific immune response. The study of interpopulation differences in TCR genes may identify those genes which are subject to selection, and also provides useful information for future genetic studies in these populations. In this study we present analysis of five TCRAV polymorphisms, for V5S1, V6S1, V8S1, V17S1, and V21S1 loci in five human populations by single-strand conformational polymorphism (SSCP) analysis. Caucasian, Chinese, Gambian, AfroCaribbean, and South American Indians (Mapuches) showed marked interpopulation variation for both the silent (V5S1, V17S1, and V21S1) and coding (V6S1 and V8S1) polymorphisms. In general the alleles were conserved in the different populations, but new, additional variants were found for V5S1 and V17S1 in Gambians and Caucasians. V6S1 overall showed the highest nucleotide diversity, and V6S1 genotype distributions were skewed away from expected values in Chinese and Mapuches. Analysis of allelic associations showed a general lack of linkage disequilibrium between the loci, which was reflected by the absence of strong population-specific haplotypes.
Adult↗
[Coastal Chilean populations: genetic markers in four locations].
BACKGROUND: Historical and anthropological data suggest the presence of descendents of Changos, Cuncos, Chonos and Yamanas, South American indian populations, in certain Chilean coastal villages. AIM: To assess the degree of South American indian admixture in Chilean coastal villages using protein markers, to complete the assessment of human biological diversity in Chile. SUBJECTS AND METHODS: ABO, Rh, MNS, Duffy and Kidd blood group systems were assessed in 47, 48, 55 and 24 individuals from Paposo, Carelmapu, Laitec and Ukika respectively. Phenotypic and gene frequencies were calculated. The degree of South American indian admixture was estimated from the ABO*O allele and Rh*dce haplotypes. RESULTS: High frequencies of ABO*O, Fy*a, Jk*b alleles, Dce and Ms haplotypes were found in all villages, consistent with the pattern expected for South American Aboriginal populations. The highest presence of South American indian admixture was present in Laitec with 80% and in Ukika with 74%. The figures for Paposo and Carelmapu were 60 and 65% respectively. CONCLUSIONS: According to South American indian admixture estimates, the genetic isolation of coastal populations is lower than that of inland subjects, suggesting that sea proximity facilitates gene flow.
Alleles↗
Genetic composition of Chilean aboriginal populations: HLA and other genetic marker variation.
Phenotypes and gene frequencies for eight genetic systems are presented for five Chilean Indian tribes. Results agree with the pattern expected for Andean Indians. Genetic distances and dendrograms were obtained separately for HLA and traditional genetic markers. The similarity of both is noteworthy. Linguistic distances exhibit a correlation with genetic distances based on traditional markers.
Chile↗
[Paternity study applying DNA polymorphism: evaluation of methods traditionally used in Chile].
Simultaneous detection of several VNTR loci using a single DNA probe is the basis of the technique called "DNA fingerprint" (DNAfp) of increasing application in parenthood identification. According to the data gathered by different laboratories worldwide, father exclusion can be made in a larger number of cases when compared with the customary tests based on erythrocyte antigens. The question could then be whether DNAfp will completely replace erythrocyte antigens tests. We report here our experience in applying DNAfp to 92 samples corresponding to 34 paternity cases and comparing these with the results obtained with the antigens of the systems ABO, Rh, MNSs, Duffy and Kidd. Most of the HaeIII/digested DNA samples produced 13 to 16 bands larger than 4.3 Kb (average 14,0761 +/- 2,205). Average band sharing between pairs of unrelated individual was 1,9107 +/- 1,083. Two cases presenting an a posteriori probability of being the father of 80.7% and 76.5% by erythrocyte antigens were clearly excluded by DNAfp. All exclusions made by antigens were confirmed by DNAfp. In the cases reported as father "rather probable" (28 cases) by DNAfp, these shared with the child 6,7407 +/- 1.7 bands on average. Because of time, cost and simplicity we favor a procedure starting with the antigens test and continuing with DNAfp only when an exclusion is not possible. Economy will increase as the number of exclusions increases.
Blood Grouping and Crossmatching↗
[Major histocompatibility system as a risk factor for alcoholic liver disease].
Several associations between alleles of the major histocompatibility system and alcoholic liver disease have been described. However, these are weak and change from one population to another. The aim of this work was to search for a possible genetic risk factor for alcoholic liver disease among Chilean alcoholics. We studied blood groups, serum proteins and HLA antigens in 39 alcoholic cirrhotics, 104 asymptomatic alcoholics and 44 non alcoholic controls. Asymptomatic alcoholics were also subjected to a percutaneous liver biopsy that showed moderate to severe histological liver damage in 46 subjects (44%). No differences in the studied genetic markers, were found among the four groups. It is concluded that this study does not confirm previously reported associations between genetic markers and alcoholic liver disease.
Adult↗
[Genetic composition of the Chilean population: the Yamanas from Ukika].
The genetic composition of a group of 24 Yamana indians that survive in Puerto Williams, Navarino Island, Chile (parallel 55 south of Tierra del Fuego), was studied. Results showed that these indians have a different genetic composition than Pehuenche indians, specially for HLA system and esterase D. This fact validates the hypothesis, based on archeological and anthropological evidence, about the paleoindian origin of Yamanas.
Blood Group Antigens↗
[Genetic composition of the Chilean population: the population from San Pedro de Atacama].
This work describes the genetic composition of atacameños from San Pedro de Atacama. The results show that a) the contribution of non-indigenous genes is relatively low, in relation to the spanish immigration period. b) the Hardy-Weinberg genetic disequilibrium for MNSs system should have biological implications c) the variant for esterasa D enzyme may be the same found in other chilean populations.
Blood Group Antigens↗
[Alcoholism and heredity. A critical update].
The etiology of alcoholism is under constant revision. This work critically examines the accumulated evidence on the degree of genetic determination of alcoholism, aiming to provide an updated view of the problem. The methodological aspects of studies performed in families, twins and adopted siblings are analyzed. The associations of alcoholism with genetic markers and diseases are reviewed, including the negative correlation between alcoholism and an aldehyde dehydrogenase variant in Japanese subjects. The association between marker genes, specially the HLA system, with organic damage and the future projection of these studies are mentioned.
Alcoholism↗
[Genetic composition of Chilean population: the Pehuenches from Trapa-Trapa].
This study describes the genetic composition of Pehuenche indians from Trapa-Trapa. The admixture analysis revealed that this group has conserved most of its pre-Columbian gene pool and therefore, is representative of the indians that lived in Southern Chile before the Spanish conquest. A relatively high frequency of a esterase D variant seems to indicate that this is a Chilean aboriginal population marker. The Chilean Pehuenches are genetically similar to their Argentinean relatives, which is not surprising since this last group crossed the Andes Mountains in historic times.
Blood Group Antigens↗
[Genetic evidence corroborates Negme's hypothesis about the greater mildness of American trypanosomiasis in Chile].
Chagas disease is present in northern and central Chile. Not more than 25% of infected individuals have had a pathologic condition presumably due to Trypanosoma cruzi. The majority of individuals with chronic infectious Chagas disease in Chile are asymptomatic in contrast to what has been observed in other South American countries. Historic and paleopathologic evidences suggest that this particular behavior could be explained by a genetic adaptation of Chilean aborigines to T cruzi. Associations between ethnic admixture, presence of Chagas disease, associated cardiac pathology and 4 blood groups (ABO, MNSs, Rh and Duffy) were investigated among inhabitants of San Pedro de Atacama in northern Chile. Cardiac pathology was determined by positive serologic reactions in individuals with abnormal electrocardiographic findings. Individuals with negative serologic results had a significantly greater aboriginal admixture (88%) compared to those with positive serology (66%). This findings supports the hypothesis of genetic adaptation explaining mildness of Chagas disease in Chile.
Adaptation, Physiological↗